New heterogeneous test statistics for the unbalanced fixed-effect nested design.

PubMed

Guo, Jiin-Huarng; Billard, L; Luh, Wei-Ming

2011-05-01

When the underlying variances are unknown or/and unequal, using the conventional F test is problematic in the two-factor hierarchical data structure. Prompted by the approximate test statistics (Welch and Alexander-Govern methods), the authors develop four new heterogeneous test statistics to test factor A and factor B nested within A for the unbalanced fixed-effect two-stage nested design under variance heterogeneity. The actual significance levels and statistical power of the test statistics were compared in a simulation study. The results show that the proposed procedures maintain better Type I error rate control and have greater statistical power than those obtained by the conventional F test in various conditions. Therefore, the proposed test statistics are recommended in terms of robustness and easy implementation. ©2010 The British Psychological Society.

Your Chi-Square Test Is Statistically Significant: Now What?

ERIC Educational Resources Information Center

Sharpe, Donald

2015-01-01

Applied researchers have employed chi-square tests for more than one hundred years. This paper addresses the question of how one should follow a statistically significant chi-square test result in order to determine the source of that result. Four approaches were evaluated: calculating residuals, comparing cells, ransacking, and partitioning. Data…

Time series, periodograms, and significance

NASA Astrophysics Data System (ADS)

Hernandez, G.

1999-05-01

The geophysical literature shows a wide and conflicting usage of methods employed to extract meaningful information on coherent oscillations from measurements. This makes it difficult, if not impossible, to relate the findings reported by different authors. Therefore, we have undertaken a critical investigation of the tests and methodology used for determining the presence of statistically significant coherent oscillations in periodograms derived from time series. Statistical significance tests are only valid when performed on the independent frequencies present in a measurement. Both the number of possible independent frequencies in a periodogram and the significance tests are determined by the number of degrees of freedom, which is the number of true independent measurements, present in the time series, rather than the number of sample points in the measurement. The number of degrees of freedom is an intrinsic property of the data, and it must be determined from the serial coherence of the time series. As part of this investigation, a detailed study has been performed which clearly illustrates the deleterious effects that the apparently innocent and commonly used processes of filtering, de-trending, and tapering of data have on periodogram analysis and the consequent difficulties in the interpretation of the statistical significance thus derived. For the sake of clarity, a specific example of actual field measurements containing unevenly-spaced measurements, gaps, etc., as well as synthetic examples, have been used to illustrate the periodogram approach, and pitfalls, leading to the (statistical) significance tests for the presence of coherent oscillations. Among the insights of this investigation are: (1) the concept of a time series being (statistically) band limited by its own serial coherence and thus having a critical sampling rate which defines one of the necessary requirements for the proper statistical design of an experiment; (2) the design of a critical test for the maximum number of significant frequencies which can be used to describe a time series, while retaining intact the variance of the test sample; (3) a demonstration of the unnecessary difficulties that manipulation of the data brings into the statistical significance interpretation of said data; and (4) the resolution and correction of the apparent discrepancy in significance results obtained by the use of the conventional Lomb-Scargle significance test, when compared with the long-standing Schuster-Walker and Fisher tests.

Color stability and degree of cure of direct composite restoratives after accelerated aging.

PubMed

Sarafianou, Aspasia; Iosifidou, Soultana; Papadopoulos, Triantafillos; Eliades, George

2007-01-01

This study evaluated the color changes and amount of remaining C = C bonds (%RDB) in three dental composites after hydrothermal- and photoaging. The materials tested were Estelite sigma, Filtek Supreme and Tetric Ceram. Specimens were fabricated from each material and subjected to L* a* b* colorimetry and FTIR spectroscopy before and after aging. Statistical evaluation of the deltaL,* deltaa,* deltab,* deltaE and %deltaRDB data was performed by one-way ANOVA and Tukey's test. The %RDB data before and after aging were statistically analyzed using two-way ANOVA and Student-Newman-Keuls test. In all cases an alpha = 0.05 significance level was used. No statistically significant differences were found in deltaL*, deltaa*, deltaE and %deltaRDB among the materials tested. Tetric Ceram demonstrated a significant difference in deltab*. All the materials showed visually perceptible (deltaE >1) but clinically acceptable values (deltaE < 3.3). Within each material group, statistically significant differences in %RDB were noticed before and after aging (p < 0.05). Filtek Supreme presented the lowest %RDB before aging, with Tetric Ceram presenting the lowest %RDB after aging (p < 0.05). The %deltaRDB mean values were statistically significantly different among all the groups tested. No correlation was found between deltaE and %deltaRDB.

Comparison between the Laser-Badal and Vernier Optometers.

DTIC Science & Technology

1988-09-01

naval aviators (SNAs). We also measured dark vcrgence in the same sample of SNAs. THE FINDINGS There was no statistically significant difference found...relatively inexperienced operator. 7. The difference between mean scores on the vernier and laser-Badal optometers was statistically significant...thus indicating that test results were reliable within instru- menrts. TAbLE 1. Test and Retest Statistics . Measure Mean SD n t-value Dark vergence

Comparisons of false negative rates from a trend test alone and from a trend test jointly with a control-high groups pairwise test in the determination of the carcinogenicity of new drugs.

PubMed

Lin, Karl K; Rahman, Mohammad A

2018-05-21

Interest has been expressed in using a joint test procedure that requires that the results of both a trend test and a pairwise comparison test between the control and the high groups be statistically significant simultaneously at the levels of significance recommended in the FDA 2001 draft guidance for industry document for the separate tests in order for the drug effect on the development of an individual tumor type to be considered as statistically significant. Results of our simulation studies show that there is a serious consequence of large inflations of the false negative rate through large decreases of false positive rate in the use of the above joint test procedure in the final interpretation of the carcinogenicity potential of a new drug if the levels of significance recommended for separate tests are used. The inflation can be as high as 204.5% of the false negative rate when the trend test alone is required to test if the effect is statistically significant. To correct the problem, new sets of levels of significance have also been developed for those who want to use the joint test in reviews of carcinogenicity studies.

40 CFR Appendix IV to Part 265 - Tests for Significance

Code of Federal Regulations, 2010 CFR

2010-07-01

... introductory statistics texts. ... student's t-test involves calculation of the value of a t-statistic for each comparison of the mean... parameter with its initial background concentration or value. The calculated value of the t-statistic must...

Effects of Math Anxiety and Perfectionism on Timed versus Untimed Math Testing in Mathematically Gifted Sixth Graders

PubMed Central

Tsui, Joanne M.; Mazzocco, Michèle M. M.

2009-01-01

This study was designed to examine the effects of math anxiety and perfectionism on math performance, under timed testing conditions, among mathematically gifted sixth graders. We found that participants had worse math performance during timed versus untimed testing, but this difference was statistically significant only when the timed condition preceded the untimed condition. We also found that children with higher levels of either math anxiety or perfectionism had a smaller performance discrepancy during timed versus untimed testing, relative to children with lower levels of math anxiety or perfectionism. There were no statistically significant gender differences in overall test performance, nor in levels of math anxiety or perfectionism; however, the difference between performance on timed and untimed math testing was statistically significant for girls, but not for boys. Implications for educators are discussed. PMID:20084180

Nursing students' attitudes toward statistics: Effect of a biostatistics course and association with examination performance.

PubMed

Kiekkas, Panagiotis; Panagiotarou, Aliki; Malja, Alvaro; Tahirai, Daniela; Zykai, Rountina; Bakalis, Nick; Stefanopoulos, Nikolaos

2015-12-01

Although statistical knowledge and skills are necessary for promoting evidence-based practice, health sciences students have expressed anxiety about statistics courses, which may hinder their learning of statistical concepts. To evaluate the effects of a biostatistics course on nursing students' attitudes toward statistics and to explore the association between these attitudes and their performance in the course examination. One-group quasi-experimental pre-test/post-test design. Undergraduate nursing students of the fifth or higher semester of studies, who attended a biostatistics course. Participants were asked to complete the pre-test and post-test forms of The Survey of Attitudes Toward Statistics (SATS)-36 scale at the beginning and end of the course respectively. Pre-test and post-test scale scores were compared, while correlations between post-test scores and participants' examination performance were estimated. Among 156 participants, post-test scores of the overall SATS-36 scale and of the Affect, Cognitive Competence, Interest and Effort components were significantly higher than pre-test ones, indicating that the course was followed by more positive attitudes toward statistics. Among 104 students who participated in the examination, higher post-test scores of the overall SATS-36 scale and of the Affect, Difficulty, Interest and Effort components were significantly but weakly correlated with higher examination performance. Students' attitudes toward statistics can be improved through appropriate biostatistics courses, while positive attitudes contribute to higher course achievements and possibly to improved statistical skills in later professional life. Copyright © 2015 Elsevier Ltd. All rights reserved.

Tests of Statistical Significance Made Sound

ERIC Educational Resources Information Center

Haig, Brian D.

2017-01-01

This article considers the nature and place of tests of statistical significance (ToSS) in science, with particular reference to psychology. Despite the enormous amount of attention given to this topic, psychology's understanding of ToSS remains deficient. The major problem stems from a widespread and uncritical acceptance of null hypothesis…

Orbital Roof Fractures as an Indicator for Concomitant Ocular Injury

DTIC Science & Technology

2017-11-12

between these two groups to indicate a statistically significant difference in mechanism of injury, subjective symptoms, CT and exam findings, and...using Pearson’s x2 test or Fisher’s exact test to indicate a statistically significant difference in mechanism of injury, subjective symptoms, CT and

Properties of permutation-based gene tests and controlling type 1 error using a summary statistic based gene test

PubMed Central

2013-01-01

Background The advent of genome-wide association studies has led to many novel disease-SNP associations, opening the door to focused study on their biological underpinnings. Because of the importance of analyzing these associations, numerous statistical methods have been devoted to them. However, fewer methods have attempted to associate entire genes or genomic regions with outcomes, which is potentially more useful knowledge from a biological perspective and those methods currently implemented are often permutation-based. Results One property of some permutation-based tests is that their power varies as a function of whether significant markers are in regions of linkage disequilibrium (LD) or not, which we show from a theoretical perspective. We therefore develop two methods for quantifying the degree of association between a genomic region and outcome, both of whose power does not vary as a function of LD structure. One method uses dimension reduction to “filter” redundant information when significant LD exists in the region, while the other, called the summary-statistic test, controls for LD by scaling marker Z-statistics using knowledge of the correlation matrix of markers. An advantage of this latter test is that it does not require the original data, but only their Z-statistics from univariate regressions and an estimate of the correlation structure of markers, and we show how to modify the test to protect the type 1 error rate when the correlation structure of markers is misspecified. We apply these methods to sequence data of oral cleft and compare our results to previously proposed gene tests, in particular permutation-based ones. We evaluate the versatility of the modification of the summary-statistic test since the specification of correlation structure between markers can be inaccurate. Conclusion We find a significant association in the sequence data between the 8q24 region and oral cleft using our dimension reduction approach and a borderline significant association using the summary-statistic based approach. We also implement the summary-statistic test using Z-statistics from an already-published GWAS of Chronic Obstructive Pulmonary Disorder (COPD) and correlation structure obtained from HapMap. We experiment with the modification of this test because the correlation structure is assumed imperfectly known. PMID:24199751

Properties of permutation-based gene tests and controlling type 1 error using a summary statistic based gene test.

PubMed

Swanson, David M; Blacker, Deborah; Alchawa, Taofik; Ludwig, Kerstin U; Mangold, Elisabeth; Lange, Christoph

2013-11-07

The advent of genome-wide association studies has led to many novel disease-SNP associations, opening the door to focused study on their biological underpinnings. Because of the importance of analyzing these associations, numerous statistical methods have been devoted to them. However, fewer methods have attempted to associate entire genes or genomic regions with outcomes, which is potentially more useful knowledge from a biological perspective and those methods currently implemented are often permutation-based. One property of some permutation-based tests is that their power varies as a function of whether significant markers are in regions of linkage disequilibrium (LD) or not, which we show from a theoretical perspective. We therefore develop two methods for quantifying the degree of association between a genomic region and outcome, both of whose power does not vary as a function of LD structure. One method uses dimension reduction to "filter" redundant information when significant LD exists in the region, while the other, called the summary-statistic test, controls for LD by scaling marker Z-statistics using knowledge of the correlation matrix of markers. An advantage of this latter test is that it does not require the original data, but only their Z-statistics from univariate regressions and an estimate of the correlation structure of markers, and we show how to modify the test to protect the type 1 error rate when the correlation structure of markers is misspecified. We apply these methods to sequence data of oral cleft and compare our results to previously proposed gene tests, in particular permutation-based ones. We evaluate the versatility of the modification of the summary-statistic test since the specification of correlation structure between markers can be inaccurate. We find a significant association in the sequence data between the 8q24 region and oral cleft using our dimension reduction approach and a borderline significant association using the summary-statistic based approach. We also implement the summary-statistic test using Z-statistics from an already-published GWAS of Chronic Obstructive Pulmonary Disorder (COPD) and correlation structure obtained from HapMap. We experiment with the modification of this test because the correlation structure is assumed imperfectly known.

A shift from significance test to hypothesis test through power analysis in medical research.

PubMed

Singh, G

2006-01-01

Medical research literature until recently, exhibited substantial dominance of the Fisher's significance test approach of statistical inference concentrating more on probability of type I error over Neyman-Pearson's hypothesis test considering both probability of type I and II error. Fisher's approach dichotomises results into significant or not significant results with a P value. The Neyman-Pearson's approach talks of acceptance or rejection of null hypothesis. Based on the same theory these two approaches deal with same objective and conclude in their own way. The advancement in computing techniques and availability of statistical software have resulted in increasing application of power calculations in medical research and thereby reporting the result of significance tests in the light of power of the test also. Significance test approach, when it incorporates power analysis contains the essence of hypothesis test approach. It may be safely argued that rising application of power analysis in medical research may have initiated a shift from Fisher's significance test to Neyman-Pearson's hypothesis test procedure.

The choice of statistical methods for comparisons of dosimetric data in radiotherapy.

PubMed

Chaikh, Abdulhamid; Giraud, Jean-Yves; Perrin, Emmanuel; Bresciani, Jean-Pierre; Balosso, Jacques

2014-09-18

Novel irradiation techniques are continuously introduced in radiotherapy to optimize the accuracy, the security and the clinical outcome of treatments. These changes could raise the question of discontinuity in dosimetric presentation and the subsequent need for practice adjustments in case of significant modifications. This study proposes a comprehensive approach to compare different techniques and tests whether their respective dose calculation algorithms give rise to statistically significant differences in the treatment doses for the patient. Statistical investigation principles are presented in the framework of a clinical example based on 62 fields of radiotherapy for lung cancer. The delivered doses in monitor units were calculated using three different dose calculation methods: the reference method accounts the dose without tissues density corrections using Pencil Beam Convolution (PBC) algorithm, whereas new methods calculate the dose with tissues density correction for 1D and 3D using Modified Batho (MB) method and Equivalent Tissue air ratio (ETAR) method, respectively. The normality of the data and the homogeneity of variance between groups were tested using Shapiro-Wilks and Levene test, respectively, then non-parametric statistical tests were performed. Specifically, the dose means estimated by the different calculation methods were compared using Friedman's test and Wilcoxon signed-rank test. In addition, the correlation between the doses calculated by the three methods was assessed using Spearman's rank and Kendall's rank tests. The Friedman's test showed a significant effect on the calculation method for the delivered dose of lung cancer patients (p <0.001). The density correction methods yielded to lower doses as compared to PBC by on average (-5 ± 4.4 SD) for MB and (-4.7 ± 5 SD) for ETAR. Post-hoc Wilcoxon signed-rank test of paired comparisons indicated that the delivered dose was significantly reduced using density-corrected methods as compared to the reference method. Spearman's and Kendall's rank tests indicated a positive correlation between the doses calculated with the different methods. This paper illustrates and justifies the use of statistical tests and graphical representations for dosimetric comparisons in radiotherapy. The statistical analysis shows the significance of dose differences resulting from two or more techniques in radiotherapy.

Effects of ozone (O3) therapy on cisplatin-induced ototoxicity in rats.

PubMed

Koçak, Hasan Emre; Taşkın, Ümit; Aydın, Salih; Oktay, Mehmet Faruk; Altınay, Serdar; Çelik, Duygu Sultan; Yücebaş, Kadir; Altaş, Bengül

2016-12-01

The aim of this study is to investigate the effect of rectal ozone and intratympanic ozone therapy on cisplatin-induced ototoxicity in rats. Eighteen female Wistar albino rats were included in our study. External auditory canal and tympanic membrane examinations were normal in all rats. The rats were randomly divided into three groups. Initially, all the rats were tested with distortion product otoacoustic emissions (DPOAE), and emissions were measured normally. All rats were injected with 5-mg/kg/day cisplatin for 3 days intraperitoneally. Ototoxicy had developed in all rats, as confirmed with DPOAE after 1 week. Rectal and intratympanic ozone therapy group was Group 1. No treatment was administered for the rats in Group 2 as the control group. The rats in Group 3 were treated with rectal ozone. All the rats were tested with DPOAE under general anesthesia, and all were sacrificed for pathological examination 1 week after ozone administration. Their cochleas were removed. The outer hair cell damage and stria vascularis damage were examined. In the statistical analysis conducted, a statistically significant difference between Group 1 and Group 2 was observed in all frequencies according to the DPOAE test. In addition, between Group 2 and Group 3, a statistically significant difference was observed in the DPOAE test. However, a statistically significant difference was not observed between Group 1 and Group 3 according to the DPOAE test. According to histopathological scoring, the outer hair cell damage score was statistically significantly high in Group 2 compared with Group 1. In addition, the outer hair cell damage score was also statistically significantly high in Group 2 compared with Group 3. Outer hair cell damage scores were low in Group 1 and Group 3, but there was no statistically significant difference between these groups. There was no statistically significant difference between the groups in terms of stria vascularis damage score examinations. Systemic ozone gas therapy is effective in the treatment of cell damage in cisplatin-induced ototoxicity. The intratympanic administration of ozone gas does not have any additional advantage over the rectal administration.

Increasing the statistical significance of entanglement detection in experiments.

PubMed

Jungnitsch, Bastian; Niekamp, Sönke; Kleinmann, Matthias; Gühne, Otfried; Lu, He; Gao, Wei-Bo; Chen, Yu-Ao; Chen, Zeng-Bing; Pan, Jian-Wei

2010-05-28

Entanglement is often verified by a violation of an inequality like a Bell inequality or an entanglement witness. Considerable effort has been devoted to the optimization of such inequalities in order to obtain a high violation. We demonstrate theoretically and experimentally that such an optimization does not necessarily lead to a better entanglement test, if the statistical error is taken into account. Theoretically, we show for different error models that reducing the violation of an inequality can improve the significance. Experimentally, we observe this phenomenon in a four-photon experiment, testing the Mermin and Ardehali inequality for different levels of noise. Furthermore, we provide a way to develop entanglement tests with high statistical significance.

Précis of statistical significance: rationale, validity, and utility.

PubMed

Chow, S L

1998-04-01

The null-hypothesis significance-test procedure (NHSTP) is defended in the context of the theory-corroboration experiment, as well as the following contrasts: (a) substantive hypotheses versus statistical hypotheses, (b) theory corroboration versus statistical hypothesis testing, (c) theoretical inference versus statistical decision, (d) experiments versus nonexperimental studies, and (e) theory corroboration versus treatment assessment. The null hypothesis can be true because it is the hypothesis that errors are randomly distributed in data. Moreover, the null hypothesis is never used as a categorical proposition. Statistical significance means only that chance influences can be excluded as an explanation of data; it does not identify the nonchance factor responsible. The experimental conclusion is drawn with the inductive principle underlying the experimental design. A chain of deductive arguments gives rise to the theoretical conclusion via the experimental conclusion. The anomalous relationship between statistical significance and the effect size often used to criticize NHSTP is more apparent than real. The absolute size of the effect is not an index of evidential support for the substantive hypothesis. Nor is the effect size, by itself, informative as to the practical importance of the research result. Being a conditional probability, statistical power cannot be the a priori probability of statistical significance. The validity of statistical power is debatable because statistical significance is determined with a single sampling distribution of the test statistic based on H0, whereas it takes two distributions to represent statistical power or effect size. Sample size should not be determined in the mechanical manner envisaged in power analysis. It is inappropriate to criticize NHSTP for nonstatistical reasons. At the same time, neither effect size, nor confidence interval estimate, nor posterior probability can be used to exclude chance as an explanation of data. Neither can any of them fulfill the nonstatistical functions expected of them by critics.

New Statistics for Testing Differential Expression of Pathways from Microarray Data

NASA Astrophysics Data System (ADS)

Siu, Hoicheong; Dong, Hua; Jin, Li; Xiong, Momiao

Exploring biological meaning from microarray data is very important but remains a great challenge. Here, we developed three new statistics: linear combination test, quadratic test and de-correlation test to identify differentially expressed pathways from gene expression profile. We apply our statistics to two rheumatoid arthritis datasets. Notably, our results reveal three significant pathways and 275 genes in common in two datasets. The pathways we found are meaningful to uncover the disease mechanisms of rheumatoid arthritis, which implies that our statistics are a powerful tool in functional analysis of gene expression data.

Biofeedback-assisted relaxation training to decrease test anxiety in nursing students.

PubMed

Prato, Catherine A; Yucha, Carolyn B

2013-01-01

Nursing students experiencing debilitating test anxiety may be unable to demonstrate their knowledge and have potential for poor academic performance. A biofeedback-assisted relaxation training program was created to reduce test anxiety. Anxiety was measured using Spielberger's Test Anxiety Inventory and monitoring peripheral skin temperature, pulse, and respiration rates during the training. Participants were introduced to diaphragmatic breathing, progressive muscle relaxation, and autogenic training. Statistically significant changes occurred in respiratory rates and skin temperatures during the diaphragmatic breathing session; respiratory rates and peripheral skin temperatures during progressive muscle relaxation session; respiratory and pulse rates, and peripheral skin temperatures during the autogenic sessions. No statistically significant difference was noted between the first and second TAI. Subjective test anxiety scores of the students did not decrease by the end of training. Autogenic training session was most effective in showing a statistically significant change in decreased respiratory and pulse rates and increased peripheral skin temperature.

Finding differentially expressed genes in high dimensional data: Rank based test statistic via a distance measure.

PubMed

Mathur, Sunil; Sadana, Ajit

2015-12-01

We present a rank-based test statistic for the identification of differentially expressed genes using a distance measure. The proposed test statistic is highly robust against extreme values and does not assume the distribution of parent population. Simulation studies show that the proposed test is more powerful than some of the commonly used methods, such as paired t-test, Wilcoxon signed rank test, and significance analysis of microarray (SAM) under certain non-normal distributions. The asymptotic distribution of the test statistic, and the p-value function are discussed. The application of proposed method is shown using a real-life data set. © The Author(s) 2011.

The Sampling Distribution and the Central Limit Theorem: What They Are and Why They're Important.

ERIC Educational Resources Information Center

Kennedy, Charlotte A.

The use of and emphasis on statistical significance testing has pervaded educational and behavioral research for many decades in spite of criticism by prominent researchers in this field. Much of the controversy is caused by lack of understanding or misinterpretations. This paper reviews criticisms of statistical significance testing and discusses…

A Statistical Analysis of Brain Morphology Using Wild Bootstrapping

PubMed Central

Ibrahim, Joseph G.; Tang, Niansheng; Rowe, Daniel B.; Hao, Xuejun; Bansal, Ravi; Peterson, Bradley S.

2008-01-01

Methods for the analysis of brain morphology, including voxel-based morphology and surface-based morphometries, have been used to detect associations between brain structure and covariates of interest, such as diagnosis, severity of disease, age, IQ, and genotype. The statistical analysis of morphometric measures usually involves two statistical procedures: 1) invoking a statistical model at each voxel (or point) on the surface of the brain or brain subregion, followed by mapping test statistics (e.g., t test) or their associated p values at each of those voxels; 2) correction for the multiple statistical tests conducted across all voxels on the surface of the brain region under investigation. We propose the use of new statistical methods for each of these procedures. We first use a heteroscedastic linear model to test the associations between the morphological measures at each voxel on the surface of the specified subregion (e.g., cortical or subcortical surfaces) and the covariates of interest. Moreover, we develop a robust test procedure that is based on a resampling method, called wild bootstrapping. This procedure assesses the statistical significance of the associations between a measure of given brain structure and the covariates of interest. The value of this robust test procedure lies in its computationally simplicity and in its applicability to a wide range of imaging data, including data from both anatomical and functional magnetic resonance imaging (fMRI). Simulation studies demonstrate that this robust test procedure can accurately control the family-wise error rate. We demonstrate the application of this robust test procedure to the detection of statistically significant differences in the morphology of the hippocampus over time across gender groups in a large sample of healthy subjects. PMID:17649909

Development of polytoxicomania in function of defence from psychoticism.

PubMed

Nenadović, Milutin M; Sapić, Rosa

2011-01-01

Polytoxicomanic proportions in subpopulations of youth have been growing steadily in recent decades, and this trend is pan-continental. Psychoticism is a psychological construct that assumes special basic dimensions of personality disintegration and cognitive functions. Psychoticism may, in general, be the basis of pathological functioning of youth and influence the patterns of thought, feelings and actions that cause dysfunction. The aim of this study was to determine the distribution of basic dimensions of psychoticism for commitment of youth to abuse psychoactive substances (PAS) in order to reduce disturbing intrapsychic experiences or manifestation of psychotic symptoms. For the purpose of this study, two groups of respondents were formed, balanced by age, gender and family structure of origin (at least one parent alive). The study applied a DELTA-9 instrument for assessment of cognitive disintegration in function of establishing psychoticism and its operationalization. The obtained results were statistically analyzed. From the parameters of descriptive statistics, the arithmetic mean was calculated with measures of dispersion. A cross-tabular analysis of variables tested was performed, as well as statistical significance with Pearson's chi2-test, and analysis of variance. Age structure and gender are approximately represented in the group of polytoximaniacs and the control group. Testing did not confirm the statistically significant difference (p > 0.5). Statistical methodology established that they significantly differed in most variables of psychoticism, polytoxicomaniacs compared with a control group of respondents. Testing confirmed a high statistical significance of differences of variables of psychoticism in the group of respondents for p < 0.001 to p < 0.01. A statistically significant representation of the dimension of psychoticism in the polytoxicomaniac group was established. The presence of factors concerning common executive dysfunction was emphasized.

A SAS macro for testing differences among three or more independent groups using Kruskal-Wallis and Nemenyi tests.

PubMed

Liu, Yuewei; Chen, Weihong

2012-02-01

As a nonparametric method, the Kruskal-Wallis test is widely used to compare three or more independent groups when an ordinal or interval level of data is available, especially when the assumptions of analysis of variance (ANOVA) are not met. If the Kruskal-Wallis statistic is statistically significant, Nemenyi test is an alternative method for further pairwise multiple comparisons to locate the source of significance. Unfortunately, most popular statistical packages do not integrate the Nemenyi test, which is not easy to be calculated by hand. We described the theory and applications of the Kruskal-Wallis and Nemenyi tests, and presented a flexible SAS macro to implement the two tests. The SAS macro was demonstrated by two examples from our cohort study in occupational epidemiology. It provides a useful tool for SAS users to test the differences among three or more independent groups using a nonparametric method.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poyer, D.A.

In this report, tests of statistical significance of five sets of variables with household energy consumption (at the point of end-use) are described. Five models, in sequence, were empirically estimated and tested for statistical significance by using the Residential Energy Consumption Survey of the US Department of Energy, Energy Information Administration. Each model incorporated additional information, embodied in a set of variables not previously specified in the energy demand system. The variable sets were generally labeled as economic variables, weather variables, household-structure variables, end-use variables, and housing-type variables. The tests of statistical significance showed each of the variable sets tomore » be highly significant in explaining the overall variance in energy consumption. The findings imply that the contemporaneous interaction of different types of variables, and not just one exclusive set of variables, determines the level of household energy consumption.« less

Effect of repeated cycles of chemical disinfection on the roughness and hardness of hard reline acrylic resins.

PubMed

Pinto, Luciana de Rezende; Acosta, Emílio José T Rodríguez; Távora, Flora Freitas Fernandes; da Silva, Paulo Maurício Batista; Porto, Vinícius Carvalho

2010-06-01

The aim of this study was to assess the effect of repeated cycles of five chemical disinfectant solutions on the roughness and hardness of three hard chairside reliners. A total of 180 circular specimens (30 mm x 6 mm) were fabricated using three hard chairside reliners (Jet; n = 60, Kooliner; n = 60, Tokuyama Rebase II Fast; n = 60), which were immersed in deionised water (control), and five disinfectant solutions (1%, 2%, 5.25% sodium hypochlorite; 2% glutaraldehyde; 4% chlorhexidine gluconate). They were tested for Knoop hardness (KHN) and surface roughness (microm), before and after 30 simulated disinfecting cycles. Data was analysed by the factorial scheme (6 x 2), two-way analysis of variance (anova), followed by Tukey's test. For Jet (from 18.74 to 13.86 KHN), Kooliner (from 14.09 to 8.72 KHN), Tokuyama (from 12.57 to 8.28 KHN) a significant decrease in hardness was observed irrespective of the solution used on all materials. For Jet (from 0.09 to 0.11 microm) there was a statistically significant increase in roughness. Kooliner (from 0.36 to 0.26 microm) presented a statistically significant decrease in roughness and Tokuyama (from 0.15 to 0.11 microm) presented no statistically significant difference after 30 days. This study showed that all disinfectant solutions promoted a statistically significant decrease in hardness, whereas with roughness, the materials tested showed a statistically significant increase, except for Tokuyama. Although statistically significant values were registered, these results could not be considered clinically significant.

Testing for significance of phase synchronisation dynamics in the EEG.

PubMed

Daly, Ian; Sweeney-Reed, Catherine M; Nasuto, Slawomir J

2013-06-01

A number of tests exist to check for statistical significance of phase synchronisation within the Electroencephalogram (EEG); however, the majority suffer from a lack of generality and applicability. They may also fail to account for temporal dynamics in the phase synchronisation, regarding synchronisation as a constant state instead of a dynamical process. Therefore, a novel test is developed for identifying the statistical significance of phase synchronisation based upon a combination of work characterising temporal dynamics of multivariate time-series and Markov modelling. We show how this method is better able to assess the significance of phase synchronisation than a range of commonly used significance tests. We also show how the method may be applied to identify and classify significantly different phase synchronisation dynamics in both univariate and multivariate datasets.

A Hybrid Template-Based Composite Classification System

DTIC Science & Technology

2009-02-01

Hybrid Classifier: Forced Decision . . . . 116 5.3.2 Forced Decision Experimental Results . . . . . 119 5.3.3 Test for Statistical Significance ...Results . . . . . . . . . . 127 5.4.2 Test for Statistical Significance : NDEC Option 129 5.5 Implementing the Hyrid Classifier with OOL Targets . 130...comple- mentary in nature . Complementary classifiers are observed by finding an optimal method for partitioning the problem space. For example, the

Evidential Value That Exercise Improves BMI z-Score in Overweight and Obese Children and Adolescents

PubMed Central

Kelley, George A.; Kelley, Kristi S.

2015-01-01

Background. Given the cardiovascular disease (CVD) related importance of understanding the true effects of exercise on adiposity in overweight and obese children and adolescents, this study examined whether there is evidential value to rule out excessive and inappropriate reporting of statistically significant results, a major problem in the published literature, with respect to exercise-induced improvements in BMI z-score among overweight and obese children and adolescents. Methods. Using data from a previous meta-analysis of 10 published studies that included 835 overweight and obese children and adolescents, a novel, recently developed approach (p-curve) was used to test for evidential value and rule out selective reporting of findings. Chi-squared tests (χ 2) were used to test for statistical significance with alpha (p) values <0.05 considered statistically significant. Results. Six of 10 findings (60%) were statistically significant. Statistically significant right-skew to rule out selective reporting was found (χ 2 = 38.8, p = 0.0001). Conversely, studies neither lacked evidential value (χ 2 = 6.8, p = 0.87) nor lacked evidential value and were intensely p-hacked (χ 2 = 4.3, p = 0.98). Conclusion. Evidential value results confirm that exercise reduces BMI z-score in overweight and obese children and adolescents, an important therapeutic strategy for treating and preventing CVD. PMID:26509145

Evidential Value That Exercise Improves BMI z-Score in Overweight and Obese Children and Adolescents.

PubMed

Kelley, George A; Kelley, Kristi S

2015-01-01

Background. Given the cardiovascular disease (CVD) related importance of understanding the true effects of exercise on adiposity in overweight and obese children and adolescents, this study examined whether there is evidential value to rule out excessive and inappropriate reporting of statistically significant results, a major problem in the published literature, with respect to exercise-induced improvements in BMI z-score among overweight and obese children and adolescents. Methods. Using data from a previous meta-analysis of 10 published studies that included 835 overweight and obese children and adolescents, a novel, recently developed approach (p-curve) was used to test for evidential value and rule out selective reporting of findings. Chi-squared tests (χ (2)) were used to test for statistical significance with alpha (p) values <0.05 considered statistically significant. Results. Six of 10 findings (60%) were statistically significant. Statistically significant right-skew to rule out selective reporting was found (χ (2) = 38.8, p = 0.0001). Conversely, studies neither lacked evidential value (χ (2) = 6.8, p = 0.87) nor lacked evidential value and were intensely p-hacked (χ (2) = 4.3, p = 0.98). Conclusion. Evidential value results confirm that exercise reduces BMI z-score in overweight and obese children and adolescents, an important therapeutic strategy for treating and preventing CVD.

BETTER STATISTICS FOR BETTER DECISIONS: REJECTING NULL HYPOTHESES STATISTICAL TESTS IN FAVOR OF REPLICATION STATISTICS

PubMed Central

SANABRIA, FEDERICO; KILLEEN, PETER R.

2008-01-01

Despite being under challenge for the past 50 years, null hypothesis significance testing (NHST) remains dominant in the scientific field for want of viable alternatives. NHST, along with its significance level p, is inadequate for most of the uses to which it is put, a flaw that is of particular interest to educational practitioners who too often must use it to sanctify their research. In this article, we review the failure of NHST and propose prep, the probability of replicating an effect, as a more useful statistic for evaluating research and aiding practical decision making. PMID:19122766

Descriptive and inferential statistical methods used in burns research.

PubMed

Al-Benna, Sammy; Al-Ajam, Yazan; Way, Benjamin; Steinstraesser, Lars

2010-05-01

Burns research articles utilise a variety of descriptive and inferential methods to present and analyse data. The aim of this study was to determine the descriptive methods (e.g. mean, median, SD, range, etc.) and survey the use of inferential methods (statistical tests) used in articles in the journal Burns. This study defined its population as all original articles published in the journal Burns in 2007. Letters to the editor, brief reports, reviews, and case reports were excluded. Study characteristics, use of descriptive statistics and the number and types of statistical methods employed were evaluated. Of the 51 articles analysed, 11(22%) were randomised controlled trials, 18(35%) were cohort studies, 11(22%) were case control studies and 11(22%) were case series. The study design and objectives were defined in all articles. All articles made use of continuous and descriptive data. Inferential statistics were used in 49(96%) articles. Data dispersion was calculated by standard deviation in 30(59%). Standard error of the mean was quoted in 19(37%). The statistical software product was named in 33(65%). Of the 49 articles that used inferential statistics, the tests were named in 47(96%). The 6 most common tests used (Student's t-test (53%), analysis of variance/co-variance (33%), chi(2) test (27%), Wilcoxon & Mann-Whitney tests (22%), Fisher's exact test (12%)) accounted for the majority (72%) of statistical methods employed. A specified significance level was named in 43(88%) and the exact significance levels were reported in 28(57%). Descriptive analysis and basic statistical techniques account for most of the statistical tests reported. This information should prove useful in deciding which tests should be emphasised in educating burn care professionals. These results highlight the need for burn care professionals to have a sound understanding of basic statistics, which is crucial in interpreting and reporting data. Advice should be sought from professionals in the fields of biostatistics and epidemiology when using more advanced statistical techniques. Copyright 2009 Elsevier Ltd and ISBI. All rights reserved.

An Evaluation of Statistical Strategies for Making Equating Function Selections. Research Report. ETS RR-08-60

ERIC Educational Resources Information Center

Moses, Tim

2008-01-01

Nine statistical strategies for selecting equating functions in an equivalent groups design were evaluated. The strategies of interest were likelihood ratio chi-square tests, regression tests, Kolmogorov-Smirnov tests, and significance tests for equated score differences. The most accurate strategies in the study were the likelihood ratio tests…

Relationship between sitting volleyball performance and field fitness of sitting volleyball players in Korea

PubMed Central

Jeoung, Bogja

2017-01-01

The purpose of this study was to evaluate the relationship between sitting volleyball performance and the field fitness of sitting volleyball players. Forty-five elite sitting volleyball players participated in 10 field fitness tests. Additionally, the players’ head coach and coach assessed their volleyball performance (receive and defense, block, attack, and serve). Data were analyzed with SPSS software version 21 by using correlation and regression analyses, and the significance level was set at P< 0.05. The results showed that chest pass, overhand throw, one-hand throw, one-hand side throw, splint, speed endurance, reaction time, and graded exercise test results had a statistically significant influence on the players’ abilities to attack, serve, and block. Grip strength, t-test, speed, and agility showed a statistically significant relationship with the players’ skill at defense and receive. Our results showed that chest pass, overhand throw, one-hand throw, one-hand side throw, speed endurance, reaction time, and graded exercise test results had a statistically significant influence on volleyball performance. PMID:29326896

Test-retest reliability of biodex system 4 pro for isometric ankle-eversion and -inversion measurement.

PubMed

Tankevicius, Gediminas; Lankaite, Doanata; Krisciunas, Aleksandras

2013-08-01

The lack of knowledge about isometric ankle testing indicates the need for research in this area. to assess test-retest reliability and to determine the optimal position for isometric ankle-eversion and -inversion testing. Test-retest reliability study. Isometric ankle eversion and inversion were assessed in 3 different dynamometer foot-plate positions: 0°, 7°, and 14° of inversion. Two maximal repetitions were performed at each angle. Both limbs were tested (40 ankles in total). The test was performed 2 times with a period of 7 d between the tests. University hospital. The study was carried out on 20 healthy athletes with no history of ankle sprains. Reliability was assessed using intraclass correlation coefficient (ICC2,1); minimal detectable change (MDC) was calculated using a 95% confidence interval. Paired t test was used to measure statistically significant changes, and P <.05 was considered statistically significant. Eversion and inversion peak torques showed high ICCs in all 3 angles (ICC values .87-.96, MDC values 3.09-6.81 Nm). Eversion peak torque was the smallest when testing at the 0° angle and gradually increased, reaching maximum values at 14° angle. The increase of eversion peak torque was statistically significant at 7 ° and 14° of inversion. Inversion peak torque showed an opposite pattern-it was the smallest when measured at the 14° angle and increased at the other 2 angles; statistically significant changes were seen only between measures taken at 0° and 14°. Isometric eversion and inversion testing using the Biodex 4 Pro system is a reliable method. The authors suggest that the angle of 7° of inversion is the best for isometric eversion and inversion testing.

Statistics 101 for Radiologists.

PubMed

Anvari, Arash; Halpern, Elkan F; Samir, Anthony E

2015-10-01

Diagnostic tests have wide clinical applications, including screening, diagnosis, measuring treatment effect, and determining prognosis. Interpreting diagnostic test results requires an understanding of key statistical concepts used to evaluate test efficacy. This review explains descriptive statistics and discusses probability, including mutually exclusive and independent events and conditional probability. In the inferential statistics section, a statistical perspective on study design is provided, together with an explanation of how to select appropriate statistical tests. Key concepts in recruiting study samples are discussed, including representativeness and random sampling. Variable types are defined, including predictor, outcome, and covariate variables, and the relationship of these variables to one another. In the hypothesis testing section, we explain how to determine if observed differences between groups are likely to be due to chance. We explain type I and II errors, statistical significance, and study power, followed by an explanation of effect sizes and how confidence intervals can be used to generalize observed effect sizes to the larger population. Statistical tests are explained in four categories: t tests and analysis of variance, proportion analysis tests, nonparametric tests, and regression techniques. We discuss sensitivity, specificity, accuracy, receiver operating characteristic analysis, and likelihood ratios. Measures of reliability and agreement, including κ statistics, intraclass correlation coefficients, and Bland-Altman graphs and analysis, are introduced. © RSNA, 2015.

Strategies for Testing Statistical and Practical Significance in Detecting DIF with Logistic Regression Models

ERIC Educational Resources Information Center

Fidalgo, Angel M.; Alavi, Seyed Mohammad; Amirian, Seyed Mohammad Reza

2014-01-01

This study examines three controversial aspects in differential item functioning (DIF) detection by logistic regression (LR) models: first, the relative effectiveness of different analytical strategies for detecting DIF; second, the suitability of the Wald statistic for determining the statistical significance of the parameters of interest; and…

Mechanical properties and radiopacity of experimental glass-silica-metal hybrid composites.

PubMed

Jandt, Klaus D; Al-Jasser, Abdullah M O; Al-Ateeq, Khalid; Vowles, Richard W; Allen, Geoff C

2002-09-01

Experimental glass-silica-metal hybrid composites (polycomposites) were developed and tested mechanically and radiographically in this fundamental pilot study. To determine whether mechanical properties of a glass-silica filled two-paste dental composite based on a Bis-GMA/polyglycol dimethacrylate blend could be improved through the incorporation of titanium (Ti) particles (particle size ranging from 1 to 3 microm) or silver-tin-copper (Ag-Sn-Cu) particles (particle size ranging from 1 to 50 microm) we measured the diametral tensile strength, fracture toughness and radiopacity of five composites. The five materials were: I, the original unmodified composite (control group); II, as group I but containing 5% (wt/wt) of Ti particles; III, as group II but with Ti particles treated with 4-methacryloyloxyethyl trimellitate anhydride (4-META) to promote Ti-resin bonding; IV, as group I but containing 5% (wt/wt) of Ag-Sn-Cu particles; and V, as group IV but with the metal particles treated with 4-META. Ten specimens of each group were tested in a standard diametral tensile strength test and a fracture toughness test using a single-edge notched sample design and five specimens of each group were tested using a radiopacity test. The diametral tensile strength increased statistically significantly after incorporation of Ti treated with 4-META, as tested by ANOVA (P=0.004) and Fisher's LSD test. A statistically significant increase of fracture toughness was observed between the control group and groups II, III and V as tested by ANOVA (P=0.003) and Fisher's LSD test. All other groups showed no statistically significant increase in diametral tensile strength and fracture toughness respectively when compared to their control groups. No statistically significant increase in radiopacity was found between the control group and the Ti filled composite, whereas a statistically significant increase in radiopacity was found between the control group and the Ag-Sn-Cu filled composite as tested by ANOVA (P=0.000) and Fisher's LSD procedure. The introduction of titanium and silver-tin-copper fillers has potential as added components in composites to provide increased mechanical strength and radiopacity, for example for use in core materials.

Depression and Self-Esteem in Early Adolescence.

PubMed

Tripković, Ingrid; Roje, Romilda; Krnić, Silvana; Nazor, Mirjana; Karin, Željka; Čapkun, Vesna

2015-06-01

Depression prevalence has increased in the last few decades, affecting younger age groups. The aim of this research was to determine the range of depression and low self-esteem in elementary school children in the city of Split. Testing was carried out at school and the sample comprised 1,549 children (714 boys and 832 girls, aged 13). Two psychological instruments were used: the Coopersmith Self-Esteem Inventory (SEI) and the Children and Adolescent Depression Scale (SDD). The average value of scores obtained by SEI test was 17.8 for all tested children. No statistically significant difference was found be-tween boys and girls. It was found that 11.9% of children showed signs of clinically significant depression, and 16.2% showed signs of depression. Statistically significant association between low self-esteem and clinically significant depression was found. No statistically significant difference among boys and girls according to dimension of cognitive depression was found, whereas statistically significant level of emotional depression was higher in girls than boys. It was found that both dimensions of depression decreased proportionally with the increase of SEI test score values: cognitive and emotional dimension of depression. The results of this study show that it is necessary to provide early detection of emotional difficulties in order to prevent serious mental disorders. Copyright© by the National Institute of Public Health, Prague 2015.

Probability as certainty: dichotomous thinking and the misuse of p values.

PubMed

Hoekstra, Rink; Finch, Sue; Kiers, Henk A L; Johnson, Addie

2006-12-01

Significance testing is widely used and often criticized. The Task Force on Statistical Inference of the American Psychological Association (TFSI, APA; Wilkinson & TFSI, 1999) addressed the use of significance testing and made recommendations that were incorporated in the fifth edition of the APA Publication Manual (APA, 2001). They emphasized the interpretation of significance testing and the importance of reporting confidence intervals and effect sizes. We examined whether 286 Psychonomic Bulletin & Review articles submitted before and after the publication of the TFSI recommendations by APA complied with these recommendations. Interpretation errors when using significance testing were still made frequently, and the new prescriptions were not yet followed on a large scale. Changing the practice of reporting statistics seems doomed to be a slow process.

The Effects of Selection Strategies for Bivariate Loglinear Smoothing Models on NEAT Equating Functions

ERIC Educational Resources Information Center

Moses, Tim; Holland, Paul W.

2010-01-01

In this study, eight statistical strategies were evaluated for selecting the parameterizations of loglinear models for smoothing the bivariate test score distributions used in nonequivalent groups with anchor test (NEAT) equating. Four of the strategies were based on significance tests of chi-square statistics (Likelihood Ratio, Pearson,…

Comparison of immediate complete denture, tooth and implant-supported overdenture on vertical dimension and muscle activity

PubMed Central

Shah, Farhan Khalid; Gebreel, Ashraf; Elshokouki, Ali hamed; Habib, Ahmed Ali

2012-01-01

PURPOSE To compare the changes in the occlusal vertical dimension, activity of masseter muscles and biting force after insertion of immediate denture constructed with conventional, tooth-supported and Implant-supported immediate mandibular complete denture. MATERIALS AND METHODS Patients were selected and treatment was carried out with all the three different concepts i.e, immediate denture constructed with conventional (Group A), tooth-supported (Group B) and Implant-supported (Group C) immediate mandibular complete dentures. Parameters of evaluation and comparison were occlusal vertical dimension measured by radiograph (at three different time intervals), Masseter muscle electromyographic (EMG) measurement by EMG analysis (at three different positions of jaws) and bite force measured by force transducer (at two different time intervals). The obtained data were statistically analyzed by using ANOVA-F test at 5% level of significance. If the F test was significant, Least Significant Difference test was performed to test further significant differences between variables. RESULTS Comparison between mean differences in occlusal vertical dimension for tested groups showed that it was only statistically significant at 1 year after immediate dentures insertion. Comparison between mean differences in wavelet packet coefficients of the electromyographic signals of masseter muscles for tested groups was not significant at rest position, but significant at initial contact position and maximum voluntary clench position. Comparison between mean differences in maximum biting force for tested groups was not statistically significant at 5% level of significance. CONCLUSION Immediate complete overdentures whether tooth or implant supported prosthesis is recommended than totally mucosal supported prosthesis. PMID:22737309

The platelet activating factor acetyl hydrolase, oxidized low-density lipoprotein, paraoxonase 1 and arylesterase levels in treated and untreated patients with polycystic ovary syndrome.

PubMed

Carlioglu, Ayse; Kaygusuz, Ikbal; Karakurt, Feridun; Gumus, Ilknur Inegol; Uysal, Aysel; Kasapoglu, Benan; Armutcu, Ferah; Uysal, Sema; Keskin, Esra Aktepe; Koca, Cemile

2014-11-01

To evaluate the platelet activating factor acetyl hydrolyze (PAF-AH), oxidized low-density lipoprotein (ox-LDL), paraoxonase 1 (PON1), arylesterase (ARE) levels and the effects of metformin and Diane-35 (ethinyl oestradiol + cyproterone acetate) therapies on these parameters and to determine the PON1 polymorphisms among PCOS patients. Ninety patients with PCOS, age 30, and body mass index-matched healthy controls were included in the study. Patients were divided into three groups: metformin treatment, Diane-35 treatment and no medication groups. The treatment with metformin or Diane-35 was continued for 6 months and all subjects were evaluated with clinical and biochemical parameters 6 months later. One-way Anova test, t test and non-parametric Mann-Whitney U tests were used for statistical analysis. PAF-AH and ox-LDL levels were statistically significantly higher in untreated PCOS patients than controls, and they were statistically significantly lower in patients treated with metformin or Diane-35 than untreated PCOS patients. In contrast, there were lower PON1 (not statistically significant) and ARE (statistically significant) levels in untreated PCOS patients than the control group and they significantly increased after metformin and Diane-35 treatments. In PCOS patients serum PON1 levels for QQ, QR and RR phenotypes were statistically significantly lower than the control group. In patients with PCOS, proatherogenic markers increase. The treatment of PCOS with metformin or Diane-35 had positive effects on lipid profile, increased PON1 level, which is a protector from atherosclerosis and decreased the proatherogenic PAF-AH and ox-LDL levels.

Cognitive Complaints After Breast Cancer Treatments: Examining the Relationship With Neuropsychological Test Performance

PubMed Central

2013-01-01

Background Cognitive complaints are reported frequently after breast cancer treatments. Their association with neuropsychological (NP) test performance is not well-established. Methods Early-stage, posttreatment breast cancer patients were enrolled in a prospective, longitudinal, cohort study prior to starting endocrine therapy. Evaluation included an NP test battery and self-report questionnaires assessing symptoms, including cognitive complaints. Multivariable regression models assessed associations among cognitive complaints, mood, treatment exposures, and NP test performance. Results One hundred eighty-nine breast cancer patients, aged 21–65 years, completed the evaluation; 23.3% endorsed higher memory complaints and 19.0% reported higher executive function complaints (>1 SD above the mean for healthy control sample). Regression modeling demonstrated a statistically significant association of higher memory complaints with combined chemotherapy and radiation treatments (P = .01), poorer NP verbal memory performance (P = .02), and higher depressive symptoms (P < .001), controlling for age and IQ. For executive functioning complaints, multivariable modeling controlling for age, IQ, and other confounds demonstrated statistically significant associations with better NP visual memory performance (P = .03) and higher depressive symptoms (P < .001), whereas combined chemotherapy and radiation treatment (P = .05) approached statistical significance. Conclusions About one in five post–adjuvant treatment breast cancer patients had elevated memory and/or executive function complaints that were statistically significantly associated with domain-specific NP test performances and depressive symptoms; combined chemotherapy and radiation treatment was also statistically significantly associated with memory complaints. These results and other emerging studies suggest that subjective cognitive complaints in part reflect objective NP performance, although their etiology and biology appear to be multifactorial, motivating further transdisciplinary research. PMID:23606729

A Statistical Analysis Plan to Support the Joint Forward Area Air Defense Test.

DTIC Science & Technology

1984-08-02

hy estahlishing a specific significance level prior to performing the statistical test (traditionally a levels are set at .01 or .05). What is often...undesirable increase in 8. For constant a levels , the power (I - 8) of a statistical test can he increased by Increasing the sample size of the test. fRef...ANOVA Iparison Test on MOP I=--ferences Exist AmongF "Upon MOP "A" Factor I "A" Factor I 1MOP " A " Levels ? I . I I I _ _ ________ IPerform k-Sample Com- I

Radiographic comparison of different concentrations of recombinant human bone morphogenetic protein with allogenic bone compared with the use of 100% mineralized cancellous bone allograft in maxillary sinus grafting.

PubMed

Froum, Stuart J; Wallace, Stephen; Cho, Sang-Choon; Khouly, Ismael; Rosenberg, Edwin; Corby, Patricia; Froum, Scott; Mascarenhas, Patrick; Tarnow, Dennis P

2014-01-01

The purpose of this study was to radiographically evaluate, then analyze, bone height, volume, and density with reference to percentage of vital bone after maxillary sinuses were grafted using two different doses of recombinant human bone morphogenetic protein 2/acellular collagen sponge (rhBMP-2/ACS) combined with mineralized cancellous bone allograft (MCBA) and a control sinus grafted with MCBA only. A total of 18 patients (36 sinuses) were used for analysis of height and volume measurements, having two of three graft combinations (one in each sinus): (1) control, MCBA only; (2) test 1, MCBA + 5.6 mL of rhBMP-2/ACS (containing 8.4 mg of rhBMP-2); and (3) test 2, MCBA + 2.8 mL of rhBMP-2/ACS (containing 4.2 mg of rhBMP-2). The study was completed with 16 patients who also had bilateral cores removed 6 to 9 months following sinus augmentation. A computer software system was used to evaluate 36 computed tomography scans. Two time points where selected for measurements of height: The results indicated that height of the grafted sinus was significantly greater in the treatment groups compared with the control. However, by the second time point, there were no statistically significant differences. Three weeks post-surgery bone volume measurements showed similar statistically significant differences between test and controls. However, prior to core removal, test group 1 with the greater dose of rhBMP-2 showed a statistically significant greater increase compared with test group 2 and the control. There was no statistically significant difference between the latter two groups. All three groups had similar volume and shrinkage. Density measurements varied from the above results, with the control showing statistically significant greater density at both time points. By contrast, the density increase over time in both rhBMP groups was similar and statistically higher than in the control group. There were strong associations between height and volume in all groups and between volume and new vital bone only in the control group. There were no statistically significant relationships observed between height and bone density or between volume and bone density for any parameter measured. More cases and monitoring of the future survival of implants placed in these augmented sinuses are needed to verify these results.

An operational definition of a statistically meaningful trend.

PubMed

Bryhn, Andreas C; Dimberg, Peter H

2011-04-28

Linear trend analysis of time series is standard procedure in many scientific disciplines. If the number of data is large, a trend may be statistically significant even if data are scattered far from the trend line. This study introduces and tests a quality criterion for time trends referred to as statistical meaningfulness, which is a stricter quality criterion for trends than high statistical significance. The time series is divided into intervals and interval mean values are calculated. Thereafter, r(2) and p values are calculated from regressions concerning time and interval mean values. If r(2) ≥ 0.65 at p ≤ 0.05 in any of these regressions, then the trend is regarded as statistically meaningful. Out of ten investigated time series from different scientific disciplines, five displayed statistically meaningful trends. A Microsoft Excel application (add-in) was developed which can perform statistical meaningfulness tests and which may increase the operationality of the test. The presented method for distinguishing statistically meaningful trends should be reasonably uncomplicated for researchers with basic statistics skills and may thus be useful for determining which trends are worth analysing further, for instance with respect to causal factors. The method can also be used for determining which segments of a time trend may be particularly worthwhile to focus on.

Statistical Analysis of Compressive and Flexural Test Results on the Sustainable Adobe Reinforced with Steel Wire Mesh

NASA Astrophysics Data System (ADS)

Jokhio, Gul A.; Syed Mohsin, Sharifah M.; Gul, Yasmeen

2018-04-01

It has been established that Adobe provides, in addition to being sustainable and economic, a better indoor air quality without spending extensive amounts of energy as opposed to the modern synthetic materials. The material, however, suffers from weak structural behaviour when subjected to adverse loading conditions. A wide range of mechanical properties has been reported in literature owing to lack of research and standardization. The present paper presents the statistical analysis of the results that were obtained through compressive and flexural tests on Adobe samples. Adobe specimens with and without wire mesh reinforcement were tested and the results were reported. The statistical analysis of these results presents an interesting read. It has been found that the compressive strength of adobe increases by about 43% after adding a single layer of wire mesh reinforcement. This increase is statistically significant. The flexural response of Adobe has also shown improvement with the addition of wire mesh reinforcement, however, the statistical significance of the same cannot be established.

Bootstrap versus Statistical Effect Size Corrections: A Comparison with Data from the Finding Embedded Figures Test.

ERIC Educational Resources Information Center

Thompson, Bruce; Melancon, Janet G.

Effect sizes have been increasingly emphasized in research as more researchers have recognized that: (1) all parametric analyses (t-tests, analyses of variance, etc.) are correlational; (2) effect sizes have played an important role in meta-analytic work; and (3) statistical significance testing is limited in its capacity to inform scientific…

Reporting Practices and Use of Quantitative Methods in Canadian Journal Articles in Psychology.

PubMed

Counsell, Alyssa; Harlow, Lisa L

2017-05-01

With recent focus on the state of research in psychology, it is essential to assess the nature of the statistical methods and analyses used and reported by psychological researchers. To that end, we investigated the prevalence of different statistical procedures and the nature of statistical reporting practices in recent articles from the four major Canadian psychology journals. The majority of authors evaluated their research hypotheses through the use of analysis of variance (ANOVA), t -tests, and multiple regression. Multivariate approaches were less common. Null hypothesis significance testing remains a popular strategy, but the majority of authors reported a standardized or unstandardized effect size measure alongside their significance test results. Confidence intervals on effect sizes were infrequently employed. Many authors provided minimal details about their statistical analyses and less than a third of the articles presented on data complications such as missing data and violations of statistical assumptions. Strengths of and areas needing improvement for reporting quantitative results are highlighted. The paper concludes with recommendations for how researchers and reviewers can improve comprehension and transparency in statistical reporting.

Simple Statistics: - Summarized!

ERIC Educational Resources Information Center

Blai, Boris, Jr.

Statistics are an essential tool for making proper judgement decisions. It is concerned with probability distribution models, testing of hypotheses, significance tests and other means of determining the correctness of deductions and the most likely outcome of decisions. Measures of central tendency include the mean, median and mode. A second…

Determining Differences in Efficacy of Two Disinfectants Using t-Tests.

ERIC Educational Resources Information Center

Brehm, Michael A.; And Others

1996-01-01

Presents an experiment to compare the effectiveness of 95% ethanol to 20% bleach as disinfectants using t-tests for the statistical analysis of the data. Reports that bleach is a better disinfectant. Discusses the statistical and practical significance of the results. (JRH)

Significance of specificity of Tinetti B-POMA test and fall risk factor in third age of life.

PubMed

Avdić, Dijana; Pecar, Dzemal

2006-02-01

As for the third age, psychophysical abilities of humans gradually decrease, while the ability of adaptation to endogenous and exogenous burdens is going down. In 1987, "Harada" et al. (1) have found out that 9.5 million persons in USA have difficulties running daily activities, while 59% of them (which is 5.6 million) are older than 65 years in age. The study has encompassed 77 questioned persons of both sexes with their average age 71.73 +/- 5.63 (scope of 65-90 years in age), chosen by random sampling. Each patient has been questioned in his/her own home and familiar to great extent with the methodology and aims of the questionnaire. Percentage of questioned women was 64.94% (50 patients) while the percentage for men was 35.06% (27 patients). As for the value of risk factor score achieved conducting the questionnaire and B-POMA test, there are statistically significant differences between men and women, as well as between patients who fell and those who never did. As for the way of life (alone or in the community), there are no significant statistical differences. Average results gained through B-POMA test in this study are statistically significantly higher in men and patients who did not provide data about falling, while there was no statistically significant difference in the way of life. In relation to the percentage of maximum number of positive answers to particular questions, regarding gender, way of life and the data about falling, there were no statistically significant differences between the value of B-POMA test and the risk factor score (the questionnaire).

Lower incisor inclination regarding different reference planes.

PubMed

Zataráin, Brenda; Avila, Josué; Moyaho, Angeles; Carrasco, Rosendo; Velasco, Carmen

2016-09-01

The purpose of this study was to assess the degree of lower incisor inclination with respect to different reference planes. It was an observational, analytical, longitudinal, prospective study conducted on 100 lateral cephalograms which were corrected according to the photograph in natural head position in order to draw the true vertical plane (TVP). The incisor mandibular plane angle (IMPA) was compensated to eliminate the variation of the mandibular plane growth type with the formula "FMApx.- 25 (FMA) + IMPApx. = compensated IMPA (IMPACOM)". As the data followed normal distribution determined by the KolmogorovSmirnov test, parametric tests were used for the statistical analysis, Ttest, ANOVA and Pearson coefficient correlation test. Statistical analysis was performed using a statistical significance of p <0.05. There is correlation between TVP and NB line (NB) (0.8614), Frankfort mandibular incisor angle (FMIA) (0.8894), IMPA (0.6351), Apo line (Apo) (0.609), IMPACOM (0.8895) and McHorris angle (MH) (0.7769). ANOVA showed statistically significant differences between the means for the 7 variables with 95% confidence level, P=0.0001. The multiple range test showed no significant difference among means: APoNB (0.88), IMPAMH (0.36), IMPANB (0.65), FMIAIMPACOM (0.01), FMIATVP (0.18), TVPIMPACOM (0.17). There was correlation among all reference planes. There were statistically significant differences among the means of the planes measured, except for IMPACOM, FMIA and TVP. The IMPA differed significantly from the IMPACOM. The compensated IMPA and the FMIA did not differ significantly from the TVP. The true horizontal plane was mismatched with Frankfort plane in 84% of the sample with a range of 19°. The true vertical plane is adequate for measuring lower incisor inclination. Sociedad Argentina de Investigación Odontológica.

[A Review on the Use of Effect Size in Nursing Research].

PubMed

Kang, Hyuncheol; Yeon, Kyupil; Han, Sang Tae

2015-10-01

The purpose of this study was to introduce the main concepts of statistical testing and effect size and to provide researchers in nursing science with guidance on how to calculate the effect size for the statistical analysis methods mainly used in nursing. For t-test, analysis of variance, correlation analysis, regression analysis which are used frequently in nursing research, the generally accepted definitions of the effect size were explained. Some formulae for calculating the effect size are described with several examples in nursing research. Furthermore, the authors present the required minimum sample size for each example utilizing G*Power 3 software that is the most widely used program for calculating sample size. It is noted that statistical significance testing and effect size measurement serve different purposes, and the reliance on only one side may be misleading. Some practical guidelines are recommended for combining statistical significance testing and effect size measure in order to make more balanced decisions in quantitative analyses.

A scan statistic to extract causal gene clusters from case-control genome-wide rare CNV data.

PubMed

Nishiyama, Takeshi; Takahashi, Kunihiko; Tango, Toshiro; Pinto, Dalila; Scherer, Stephen W; Takami, Satoshi; Kishino, Hirohisa

2011-05-26

Several statistical tests have been developed for analyzing genome-wide association data by incorporating gene pathway information in terms of gene sets. Using these methods, hundreds of gene sets are typically tested, and the tested gene sets often overlap. This overlapping greatly increases the probability of generating false positives, and the results obtained are difficult to interpret, particularly when many gene sets show statistical significance. We propose a flexible statistical framework to circumvent these problems. Inspired by spatial scan statistics for detecting clustering of disease occurrence in the field of epidemiology, we developed a scan statistic to extract disease-associated gene clusters from a whole gene pathway. Extracting one or a few significant gene clusters from a global pathway limits the overall false positive probability, which results in increased statistical power, and facilitates the interpretation of test results. In the present study, we applied our method to genome-wide association data for rare copy-number variations, which have been strongly implicated in common diseases. Application of our method to a simulated dataset demonstrated the high accuracy of this method in detecting disease-associated gene clusters in a whole gene pathway. The scan statistic approach proposed here shows a high level of accuracy in detecting gene clusters in a whole gene pathway. This study has provided a sound statistical framework for analyzing genome-wide rare CNV data by incorporating topological information on the gene pathway.

Cognitive Stimulation of Elderly Residents in Social Protection Centers in Cartagena, 2014.

PubMed

Melguizo Herrera, Estela; Bertel De La Hoz, Anyel; Paternina Osorio, Diego; Felfle Fuentes, Yurani; Porto Osorio, Leidy

To determine the effectiveness of a program of cognitive stimulation of the elderly residents in Social Protection Centers in Cartagena, 2014. Quasi-experimental study with pre and post tests in control and experimental groups. A sample of 37 elderly residents in Social Protection Centers participated: 23 in the experimental group and 14 in the control group. A survey and a mental evaluation test (Pfeiffer) were applied. The experimental group participated in 10 sessions of cognitive stimulation. The paired t-test showed statistically significant differences in the Pfeiffer test, pre and post intervention, compared to the experimental group (P=.0005). The unpaired t-test showed statistically significant differences in Pfeiffer test results to the experimental and control groups (P=.0450). The analysis of the main components showed that more interrelated variables were: age, diseases, number of errors and test results; which were grouped around the disease variable, with a negative association. The intervention demonstrated a statistically significant improvement in cognitive functionality of the elderly. Nursing can lead this type of intervention. It should be studied further to strengthen and clarify these results. Copyright © 2016 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

Inhibition of Orthopaedic Implant Infections by Immunomodulatory Effects of Host Defense Peptides

DTIC Science & Technology

2014-12-01

significance was determined by t- tests or by one-way analysis of variance (ANOVA) followed by Bonferroni post hoc tests in experiments with multiple...groups. Non- parametric Mann-Whitney tests , Kruskal-Wallis ANOVA followed by Newman-Kuels post hoc tests , or van Elteren’s two-way tests were applied to...in D, and black symbols in A), statistical analysis was by one-way ANOVA followed by Bonferroni versus control, post hoc tests . Otherwise, statistical

Acceptability of HIV/AIDS testing among pre-marital couples in Iran (2012)

PubMed Central

Ayatollahi, Jamshid; Nasab Sarab, Mohammad Ali Bagheri; Sharifi, Mohammad Reza; Shahcheraghi, Seyed Hossein

2014-01-01

Background: Human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) is a lifestyle-related disease. This disease is transmitted through unprotected sex, contaminated needles, infected blood transfusion and from mother to child during pregnancy and delivery. Prevention of infection with HIV, mainly through safe sex and needle exchange programmes is a solution to prevent the spread of the disease. Knowledge about HIV state helps to prevent and subsequently reduce the harm to the later generation. The purpose of this study was to assess the willingness rate of couples referred to the family regulation pre-marital counselling centre for performing HIV test before marriage in Yazd. Patients and Methods: In this descriptive study, a simple random sampling was done among people referred to Akbari clinic. The couples were 1000 men and 1000 women referred to the premarital counselling centre for pre-marital HIV testing in Yazd in the year 2012. They were in situations of pregnancy, delivery or nursing and milking. The data were analyzed using Statistical Package for the Social Sciences (SPSS) software and chi-square statistical test. Results: There was a significant statistical difference between the age groups about willingness for HIV testing before marriage (P < 0.001) and also positive comments about HIV testing in asymptomatic individuals (P < 0.001). This study also proved a significant statistical difference between the two gender groups about willingness to marry after HIV positive test of their wives. Conclusion: The willingness rate of couples to undergo HIV testing before marriage was significant. Therefore, HIV testing before marriage as a routine test was suggested. PMID:25114363

Acceptability of HIV/AIDS testing among pre-marital couples in Iran (2012).

PubMed

Ayatollahi, Jamshid; Nasab Sarab, Mohammad Ali Bagheri; Sharifi, Mohammad Reza; Shahcheraghi, Seyed Hossein

2014-07-01

Human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) is a lifestyle-related disease. This disease is transmitted through unprotected sex, contaminated needles, infected blood transfusion and from mother to child during pregnancy and delivery. Prevention of infection with HIV, mainly through safe sex and needle exchange programmes is a solution to prevent the spread of the disease. Knowledge about HIV state helps to prevent and subsequently reduce the harm to the later generation. The purpose of this study was to assess the willingness rate of couples referred to the family regulation pre-marital counselling centre for performing HIV test before marriage in Yazd. In this descriptive study, a simple random sampling was done among people referred to Akbari clinic. The couples were 1000 men and 1000 women referred to the premarital counselling centre for pre-marital HIV testing in Yazd in the year 2012. They were in situations of pregnancy, delivery or nursing and milking. The data were analyzed using Statistical Package for the Social Sciences (SPSS) software and chi-square statistical test. There was a significant statistical difference between the age groups about willingness for HIV testing before marriage (P < 0.001) and also positive comments about HIV testing in asymptomatic individuals (P < 0.001). This study also proved a significant statistical difference between the two gender groups about willingness to marry after HIV positive test of their wives. The willingness rate of couples to undergo HIV testing before marriage was significant. Therefore, HIV testing before marriage as a routine test was suggested.

Evaluation of moxifloxacin-hydroxyapatite composite graft in the regeneration of intrabony defects: A clinical, radiographic, and microbiological study

PubMed Central

Nagarjuna Reddy, Y. V.; Deepika, P. C.; Venkatesh, M. P.; Rajeshwari, K. G.

2016-01-01

Background: The formation of new connective periodontal attachment is contingent upon the elimination or marked reduction of pathogens at the treated periodontal site. An anti-microbial agent, i.e. moxifloxacin has been incorporated into the bone graft to control infection and facilitate healing during and after periodontal therapy. Materials and Methods: By purposive sampling, 15 patients with at least two contralateral vertical defect sites were selected. The selected sites in each individual were divided randomly into test and control sites according to split-mouth design. Test site received moxifloxacin-hydroxyapatite composite graft and control site received hydroxyapatite-placebo gel composite graft. Probing depth (PD) and Clinical attachment level (CAL) were assessed at baseline, 3, 6, 9, and 12 months. Bone probing depth (BPD) and hard tissue parameters such as amount of defect fill, percentage of defect fill, and changes in alveolar crest were assessed at baseline, 6, and 12 months. Changes in subgingival microflora were also assessed by culturing the subgingival plaque samples at baseline and at 3-month follow-up. The clinical, radiographic, and microbiological data obtained were subjected to statistical analysis using descriptive statistics, paired sample t-test, independent t-test, and contingency test. Results: On intragroup comparison at test and control sites, there was a significant improvement in all clinical and radiographic parameters. However, on intergroup comparison of the same, there was no statistically significant difference between test and control sites at any interval. Although test sites showed slightly higher amount of bone fill, it was not statistically significant. There was a significant reduction in the counts of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis at both sites from baseline to 3 months. In addition, there was a significant reduction at test sites as compared to control sites at 3-month follow-up (P = 0.003 and P = 0.013). Conclusion: The reduction in microbial counts found in test sites at 3-month follow-up could not bring similar significant improvements in the clinical and radiographic parameters though the test sites showed slightly higher bone fill. PMID:27630501

Quantification and statistical significance analysis of group separation in NMR-based metabonomics studies

PubMed Central

Goodpaster, Aaron M.; Kennedy, Michael A.

2015-01-01

Currently, no standard metrics are used to quantify cluster separation in PCA or PLS-DA scores plots for metabonomics studies or to determine if cluster separation is statistically significant. Lack of such measures makes it virtually impossible to compare independent or inter-laboratory studies and can lead to confusion in the metabonomics literature when authors putatively identify metabolites distinguishing classes of samples based on visual and qualitative inspection of scores plots that exhibit marginal separation. While previous papers have addressed quantification of cluster separation in PCA scores plots, none have advocated routine use of a quantitative measure of separation that is supported by a standard and rigorous assessment of whether or not the cluster separation is statistically significant. Here quantification and statistical significance of separation of group centroids in PCA and PLS-DA scores plots are considered. The Mahalanobis distance is used to quantify the distance between group centroids, and the two-sample Hotelling's T2 test is computed for the data, related to an F-statistic, and then an F-test is applied to determine if the cluster separation is statistically significant. We demonstrate the value of this approach using four datasets containing various degrees of separation, ranging from groups that had no apparent visual cluster separation to groups that had no visual cluster overlap. Widespread adoption of such concrete metrics to quantify and evaluate the statistical significance of PCA and PLS-DA cluster separation would help standardize reporting of metabonomics data. PMID:26246647

Power, effects, confidence, and significance: an investigation of statistical practices in nursing research.

PubMed

Gaskin, Cadeyrn J; Happell, Brenda

2014-05-01

To (a) assess the statistical power of nursing research to detect small, medium, and large effect sizes; (b) estimate the experiment-wise Type I error rate in these studies; and (c) assess the extent to which (i) a priori power analyses, (ii) effect sizes (and interpretations thereof), and (iii) confidence intervals were reported. Statistical review. Papers published in the 2011 volumes of the 10 highest ranked nursing journals, based on their 5-year impact factors. Papers were assessed for statistical power, control of experiment-wise Type I error, reporting of a priori power analyses, reporting and interpretation of effect sizes, and reporting of confidence intervals. The analyses were based on 333 papers, from which 10,337 inferential statistics were identified. The median power to detect small, medium, and large effect sizes was .40 (interquartile range [IQR]=.24-.71), .98 (IQR=.85-1.00), and 1.00 (IQR=1.00-1.00), respectively. The median experiment-wise Type I error rate was .54 (IQR=.26-.80). A priori power analyses were reported in 28% of papers. Effect sizes were routinely reported for Spearman's rank correlations (100% of papers in which this test was used), Poisson regressions (100%), odds ratios (100%), Kendall's tau correlations (100%), Pearson's correlations (99%), logistic regressions (98%), structural equation modelling/confirmatory factor analyses/path analyses (97%), and linear regressions (83%), but were reported less often for two-proportion z tests (50%), analyses of variance/analyses of covariance/multivariate analyses of variance (18%), t tests (8%), Wilcoxon's tests (8%), Chi-squared tests (8%), and Fisher's exact tests (7%), and not reported for sign tests, Friedman's tests, McNemar's tests, multi-level models, and Kruskal-Wallis tests. Effect sizes were infrequently interpreted. Confidence intervals were reported in 28% of papers. The use, reporting, and interpretation of inferential statistics in nursing research need substantial improvement. Most importantly, researchers should abandon the misleading practice of interpreting the results from inferential tests based solely on whether they are statistically significant (or not) and, instead, focus on reporting and interpreting effect sizes, confidence intervals, and significance levels. Nursing researchers also need to conduct and report a priori power analyses, and to address the issue of Type I experiment-wise error inflation in their studies. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Research design and statistical methods in Pakistan Journal of Medical Sciences (PJMS).

PubMed

Akhtar, Sohail; Shah, Syed Wadood Ali; Rafiq, M; Khan, Ajmal

2016-01-01

This article compares the study design and statistical methods used in 2005, 2010 and 2015 of Pakistan Journal of Medical Sciences (PJMS). Only original articles of PJMS were considered for the analysis. The articles were carefully reviewed for statistical methods and designs, and then recorded accordingly. The frequency of each statistical method and research design was estimated and compared with previous years. A total of 429 articles were evaluated (n=74 in 2005, n=179 in 2010, n=176 in 2015) in which 171 (40%) were cross-sectional and 116 (27%) were prospective study designs. A verity of statistical methods were found in the analysis. The most frequent methods include: descriptive statistics (n=315, 73.4%), chi-square/Fisher's exact tests (n=205, 47.8%) and student t-test (n=186, 43.4%). There was a significant increase in the use of statistical methods over time period: t-test, chi-square/Fisher's exact test, logistic regression, epidemiological statistics, and non-parametric tests. This study shows that a diverse variety of statistical methods have been used in the research articles of PJMS and frequency improved from 2005 to 2015. However, descriptive statistics was the most frequent method of statistical analysis in the published articles while cross-sectional study design was common study design.

Critical Thinking Skills of U.S. Air Force Senior and Intermediate Developmental Education Students

DTIC Science & Technology

2016-02-16

SAASS), and Air War College (AWC). T-tests indicated no statistically significant difference in the CT skills of the sample of ACSC and AWC students...hypothesis that there was no statistically significant difference in the CT skills of IDE and SDE students. SAASS, as a more selective advanced studies...potential to develop CT skills, concluding, “students in the experimental group performed at a statistically significantly higher level than students in

Cosmic shear measurements with Dark Energy Survey Science Verification data

DOE PAGES

Becker, M. R.

2016-07-06

Here, we present measurements of weak gravitational lensing cosmic shear two-point statistics using Dark Energy Survey Science Verification data. We demonstrate that our results are robust to the choice of shear measurement pipeline, either ngmix or im3shape, and robust to the choice of two-point statistic, including both real and Fourier-space statistics. Our results pass a suite of null tests including tests for B-mode contamination and direct tests for any dependence of the two-point functions on a set of 16 observing conditions and galaxy properties, such as seeing, airmass, galaxy color, galaxy magnitude, etc. We use a large suite of simulationsmore » to compute the covariance matrix of the cosmic shear measurements and assign statistical significance to our null tests. We find that our covariance matrix is consistent with the halo model prediction, indicating that it has the appropriate level of halo sample variance. We also compare the same jackknife procedure applied to the data and the simulations in order to search for additional sources of noise not captured by the simulations. We find no statistically significant extra sources of noise in the data. The overall detection significance with tomography for our highest source density catalog is 9.7σ. Cosmological constraints from the measurements in this work are presented in a companion paper.« less

Decadal power in land air temperatures: Is it statistically significant?

NASA Astrophysics Data System (ADS)

Thejll, Peter A.

2001-12-01

The geographical distribution and properties of the well-known 10-11 year signal in terrestrial temperature records is investigated. By analyzing the Global Historical Climate Network data for surface air temperatures we verify that the signal is strongest in North America and is similar in nature to that reported earlier by R. G. Currie. The decadal signal is statistically significant for individual stations, but it is not possible to show that the signal is statistically significant globally, using strict tests. In North America, during the twentieth century, the decadal variability in the solar activity cycle is associated with the decadal part of the North Atlantic Oscillation index series in such a way that both of these signals correspond to the same spatial pattern of cooling and warming. A method for testing statistical results with Monte Carlo trials on data fields with specified temporal structure and specific spatial correlation retained is presented.

Estimation of the geochemical threshold and its statistical significance

USGS Publications Warehouse

Miesch, A.T.

1981-01-01

A statistic is proposed for estimating the geochemical threshold and its statistical significance, or it may be used to identify a group of extreme values that can be tested for significance by other means. The statistic is the maximum gap between adjacent values in an ordered array after each gap has been adjusted for the expected frequency. The values in the ordered array are geochemical values transformed by either ln(?? - ??) or ln(?? - ??) and then standardized so that the mean is zero and the variance is unity. The expected frequency is taken from a fitted normal curve with unit area. The midpoint of an adjusted gap that exceeds the corresponding critical value may be taken as an estimate of the geochemical threshold, and the associated probability indicates the likelihood that the threshold separates two geochemical populations. The adjusted gap test may fail to identify threshold values if the variation tends to be continuous from background values to the higher values that reflect mineralized ground. However, the test will serve to identify other anomalies that may be too subtle to have been noted by other means. ?? 1981.

Monitoring Items in Real Time to Enhance CAT Security

ERIC Educational Resources Information Center

Zhang, Jinming; Li, Jie

2016-01-01

An IRT-based sequential procedure is developed to monitor items for enhancing test security. The procedure uses a series of statistical hypothesis tests to examine whether the statistical characteristics of each item under inspection have changed significantly during CAT administration. This procedure is compared with a previously developed…

Significance testing of rules in rule-based models of human problem solving

NASA Technical Reports Server (NTRS)

Lewis, C. M.; Hammer, J. M.

1986-01-01

Rule-based models of human problem solving have typically not been tested for statistical significance. Three methods of testing rules - analysis of variance, randomization, and contingency tables - are presented. Advantages and disadvantages of the methods are also described.

Effect of cefuroxime and moxifloxacin on Staphylococcus epidermidis adherence to intraocular lenses.

PubMed

Karadağ, Serhat; Ozkan, Berna; Karabaş, V Levent; Alintaş, Ozgül; Yumuk, Zeki; Cağlar, Yusuf

2009-12-01

To investigate and compare the effect of cefuroxime and moxifloxacin on adhesion of Staphylococcus epidermidis to intraocular lenses (IOLs). Experimental study. The 3-pieced hydrophobic acrylic lenses were contaminated with S. epidermidis (American Type Culture Collection 35983) solutions containing 108 colony-forming units. IOLs were inoculated into test tubes containing tryptic soy broth after being held in antibiotic solutions for 15 minutes. Sonication and vortex procedures were performed in order to remove all the remaining bacteria. From each tube 10 microL and 100 microL was taken and inoculated into sheep blood agar. The colonies were counted overnight. The statistical analyses were made using one-way ANOVA, Turkey Honestly Significant Differences test (HSD) and independent t tests, and a p value less than 0.05 was considered statistically significant. Overall, the mean numbers of colony-forming units on the lenses that were held in control, cefuroxime, moxifloxacin 0.5 mg/0.1 mL and moxifloxacin 0.1 mg/0.1 mL solutions were 1398 (SE 10.01 x 10(3)), 29.9 (SE 1.16 x 10(3)), 0.23 (SD 0.04 x 10(3)), and 0.41 (SD 0.05 x 10(3)), respectively. The evaluation using one-way ANOVA and Turkey HSD tests revealed significant statistical differences among the groups (p = 0.000). The evaluation using independent t tests revealed significant statistical differences between the 2 moxifloxacin groups (p < 0.05). Our results suggest that moxifloxacin and cefuroxime significantly inhibit bacterial adherence to IOLs. The effect of moxifloxacin on inhibition of bacterial adherence was significantly greater than that of cefuroxime. For this reason moxifloxacin might be considered as a better prophylactic agent.

Antimicrobial and anti-adherence activity of various combinations of coffee-chicory solutions on Streptococcus mutans: An in-vitro study

PubMed Central

Sharma, Rama; Reddy, Vamsi Krishna L; Prashant, GM; Ojha, Vivek; Kumar, Naveen PG

2014-01-01

Context: Several studies have demonstrated the activity of natural plants on the dental biofilm and caries development. But few studies on the antimicrobial activity of coffee-based solutions were found in the literature. Further there was no study available to check the antimicrobial effect of coffee solutions with different percentages of chicory in it. Aims: To evaluate the antimicrobial activity of different combinations of coffee-chicory solutions and their anti-adherence effect on Streptococcus mutans to glass surface. Materials and Methods: Test solutions were prepared. For antimicrobial activity testing, tubes containing test solution and culture medium were inoculated with a suspension of S. mutans followed by plating on Brain Heart Infusion (BHI) agar. S. mutans adherence to glass in presence of the different test solutions was also tested. The number of adhered bacteria (CFU/mL) was determined by plating method. Statistical Analysis: Statistical significance was measured using one way ANOVA followed by Tukey's post hoc test. P value < 0.05 was considered statistically significant. Results: Pure chicory had shown significantly less bacterial count compared to all other groups. Groups IV and V had shown significant reduction in bacterial counts over the period of 4 hrs. Regarding anti-adherence effect, group I-IV had shown significantly less adherence of bacteria to glass surface. Conclusions: Chicory exerted antibacterial effect against S. mutans while coffee reduced significantly the adherence of S. mutans to the glass surface. PMID:25328299

The Relationship between Dental Follicle Width and Maxillary Impacted Canines' Descriptive and Resorptive Features Using Cone-Beam Computed Tomography.

PubMed

Dağsuyu, İlhan Metin; Okşayan, Rıdvan; Kahraman, Fatih; Aydın, Mehmet; Bayrakdar, İbrahim Şevki; Uğurlu, Mehmet

2017-01-01

To assess the relationship between dental follicle width and maxillary impacted canines' descriptive and resorptive features with three-dimensional (3D) cone-beam computed tomography (CBCT). The study comprised 102 patients with cone-beam computed tomography 3D images and a total of 140 impacted canines. The association between maxillary impacted canine dental follicle width and the variables of gender, impaction side (right and left), localization of impacted canine (buccal, central, and palatal), and resorption of the adjacent laterals was compared. Measurements were analyzed with Student's t -test, Kruskal-Wallis test, and Mann-Whitney U statistical test. According to gender, no statistically significant differences were found in the follicle size of the maxillary impacted canine between males and females ( p > 0.05). Widths of the follicles were determined for the right and left impaction sides, and no statistically significant relation was found ( p > 0.05). There were statistically significant differences between root resorption degrees of lateral incisors and maxillary impacted canine follicle width ( p < 0.05). Statistically significant higher follicle width values were present in degree 2 (mild) resorption than in degree 1 (no) and degree 3 (moderate) resorption samples ( p < 0.05). No significant correlation was found between follicle width and the variables of gender, impaction side, and localization of maxillary impacted canines. Our study could not confirm that increased dental follicle width of the maxillary impacted canines exhibited more resorption risk for the adjacent lateral incisors.

Evaluation of cognitive characteristics of patients developing manifestations of parkinsonism secondary to long-term ephedrone use.

PubMed

Koksal, Ayhan; Keskinkılıc, Cahit; Sozmen, Mehmet Vedat; Dirican, Ayten Ceyhan; Aysal, Fikret; Altunkaynak, Yavuz; Baybas, Sevim

2014-01-01

In this study, cognitive functions of 9 patients developing parkinsonism due to chronic manganese intoxication by intravenous methcathinone solution were investigated using detailed neuropsychometric tests. Attention deficit, verbal and nonverbal memory, visuospatial function, constructive ability, language, and executive (frontal) functions of 9 patients who were admitted to our clinic with manifestations of chronic manganese intoxication and 9 control subjects were assessed using neuropsychometric tests. Two years later, detailed repeat neuropsychometric tests were performed in the patient group. The results were evaluated using the χ(2) test, Fisher's exact probability test, Student's t test and the Mann-Whitney U test. While there was no statistically significant difference between the two groups in language functions, visuospatial functions and constructive ability, a statistically significant difference was noted between both groups regarding attention (p = 0.032), calculation (p = 0.004), recall and recognition domains of verbal memory, nonverbal memory (p = 0.021) and some domains of frontal functions (Stroop-5 and spontaneous recovery) (p = 0.022 and 0.012). Repeat neuropsychometric test results of the patients were not statistically significant 2 years later. It has been observed that cognitive dysfunction seen in parkinsonism secondary to chronic manganese intoxication may be long-lasting and may not recover as observed in motor dysfunction. © 2014 S. Karger AG, Basel.

Assessment of statistical significance and clinical relevance.

PubMed

Kieser, Meinhard; Friede, Tim; Gondan, Matthias

2013-05-10

In drug development, it is well accepted that a successful study will demonstrate not only a statistically significant result but also a clinically relevant effect size. Whereas standard hypothesis tests are used to demonstrate the former, it is less clear how the latter should be established. In the first part of this paper, we consider the responder analysis approach and study the performance of locally optimal rank tests when the outcome distribution is a mixture of responder and non-responder distributions. We find that these tests are quite sensitive to their planning assumptions and have therefore not really any advantage over standard tests such as the t-test and the Wilcoxon-Mann-Whitney test, which perform overall well and can be recommended for applications. In the second part, we present a new approach to the assessment of clinical relevance based on the so-called relative effect (or probabilistic index) and derive appropriate sample size formulae for the design of studies aiming at demonstrating both a statistically significant and clinically relevant effect. Referring to recent studies in multiple sclerosis, we discuss potential issues in the application of this approach. Copyright © 2012 John Wiley & Sons, Ltd.

Common Scientific and Statistical Errors in Obesity Research

PubMed Central

George, Brandon J.; Beasley, T. Mark; Brown, Andrew W.; Dawson, John; Dimova, Rositsa; Divers, Jasmin; Goldsby, TaShauna U.; Heo, Moonseong; Kaiser, Kathryn A.; Keith, Scott; Kim, Mimi Y.; Li, Peng; Mehta, Tapan; Oakes, J. Michael; Skinner, Asheley; Stuart, Elizabeth; Allison, David B.

2015-01-01

We identify 10 common errors and problems in the statistical analysis, design, interpretation, and reporting of obesity research and discuss how they can be avoided. The 10 topics are: 1) misinterpretation of statistical significance, 2) inappropriate testing against baseline values, 3) excessive and undisclosed multiple testing and “p-value hacking,” 4) mishandling of clustering in cluster randomized trials, 5) misconceptions about nonparametric tests, 6) mishandling of missing data, 7) miscalculation of effect sizes, 8) ignoring regression to the mean, 9) ignoring confirmation bias, and 10) insufficient statistical reporting. We hope that discussion of these errors can improve the quality of obesity research by helping researchers to implement proper statistical practice and to know when to seek the help of a statistician. PMID:27028280

Evaluation of Three Different Processing Techniques in the Fabrication of Complete Dentures

PubMed Central

Chintalacheruvu, Vamsi Krishna; Balraj, Rajasekaran Uttukuli; Putchala, Lavanya Sireesha; Pachalla, Sreelekha

2017-01-01

Aims and Objectives: The objective of the present study is to compare the effectiveness of three different processing techniques and to find out the accuracy of processing techniques through number of occlusal interferences and increase in vertical dimension after denture processing. Materials and Methods: A cross-sectional study was conducted on a sample of 18 patients indicated for complete denture fabrication was selected for the study and they were divided into three subgroups. Three processing techniques, compression molding and injection molding using prepolymerized resin and unpolymerized resin, were used to fabricate dentures for each of the groups. After processing, laboratory-remounted dentures were evaluated for number of occlusal interferences in centric and eccentric relations and change in vertical dimension through vertical pin rise in articulator. Data were analyzed using statistical test ANOVA and SPSS software version 19.0 by IBM was used. Results: Data obtained from three groups were subjected to one-way ANOVA test. After ANOVA test, results with significant variations were subjected to post hoc test. Number of occlusal interferences with compression molding technique was reported to be more in both centric and eccentric positions as compared to the two injection molding techniques with statistical significance in centric, protrusive, right lateral nonworking, and left lateral working positions (P < 0.05). Mean vertical pin rise (0.52 mm) was reported to more in compression molding technique as compared to injection molding techniques, which is statistically significant (P < 0.001). Conclusions: Within the limitations of this study, injection molding techniques exhibited less processing errors as compared to compression molding technique with statistical significance. There was no statistically significant difference in processing errors reported within two injection molding systems. PMID:28713763

Evaluation of Three Different Processing Techniques in the Fabrication of Complete Dentures.

PubMed

Chintalacheruvu, Vamsi Krishna; Balraj, Rajasekaran Uttukuli; Putchala, Lavanya Sireesha; Pachalla, Sreelekha

2017-06-01

The objective of the present study is to compare the effectiveness of three different processing techniques and to find out the accuracy of processing techniques through number of occlusal interferences and increase in vertical dimension after denture processing. A cross-sectional study was conducted on a sample of 18 patients indicated for complete denture fabrication was selected for the study and they were divided into three subgroups. Three processing techniques, compression molding and injection molding using prepolymerized resin and unpolymerized resin, were used to fabricate dentures for each of the groups. After processing, laboratory-remounted dentures were evaluated for number of occlusal interferences in centric and eccentric relations and change in vertical dimension through vertical pin rise in articulator. Data were analyzed using statistical test ANOVA and SPSS software version 19.0 by IBM was used. Data obtained from three groups were subjected to one-way ANOVA test. After ANOVA test, results with significant variations were subjected to post hoc test. Number of occlusal interferences with compression molding technique was reported to be more in both centric and eccentric positions as compared to the two injection molding techniques with statistical significance in centric, protrusive, right lateral nonworking, and left lateral working positions ( P < 0.05). Mean vertical pin rise (0.52 mm) was reported to more in compression molding technique as compared to injection molding techniques, which is statistically significant ( P < 0.001). Within the limitations of this study, injection molding techniques exhibited less processing errors as compared to compression molding technique with statistical significance. There was no statistically significant difference in processing errors reported within two injection molding systems.

Accelerated aging effects on surface hardness and roughness of lingual retainer adhesives.

PubMed

Ramoglu, Sabri Ilhan; Usumez, Serdar; Buyukyilmaz, Tamer

2008-01-01

To test the null hypothesis that accelerated aging has no effect on the surface microhardness and roughness of two light-cured lingual retainer adhesives. Ten samples of light-cured materials, Transbond Lingual Retainer (3M Unitek) and Light Cure Retainer (Reliance) were cured with a halogen light for 40 seconds. Vickers hardness and surface roughness were measured before and after accelerated aging of 300 hours in a weathering tester. Differences between mean values were analyzed for statistical significance using a t-test. The level of statistical significance was set at P < .05. The mean Vickers hardness of Transbond Lingual Retainer was 62.8 +/- 3.5 and 79.6 +/- 4.9 before and after aging, respectively. The mean Vickers hardness of Light Cure Retainer was 40.3 +/- 2.6 and 58.3 +/- 4.3 before and after aging, respectively. Differences in both groups were statistically significant (P < .001). Following aging, mean surface roughness was changed from 0.039 microm to 0.121 microm and from 0.021 microm to 0.031 microm for Transbond Lingual Retainer and Light Cure Retainer, respectively. The roughening of Transbond Lingual Retainer with aging was statistically significant (P < .05), while the change in the surface roughness of Light Cure Retainer was not (P > .05). Accelerated aging significantly increased the surface microhardness of both light-cured retainer adhesives tested. It also significantly increased the surface roughness of the Transbond Lingual Retainer.

Testing statistical self-similarity in the topology of river networks

USGS Publications Warehouse

Troutman, Brent M.; Mantilla, Ricardo; Gupta, Vijay K.

2010-01-01

Recent work has demonstrated that the topological properties of real river networks deviate significantly from predictions of Shreve's random model. At the same time the property of mean self-similarity postulated by Tokunaga's model is well supported by data. Recently, a new class of network model called random self-similar networks (RSN) that combines self-similarity and randomness has been introduced to replicate important topological features observed in real river networks. We investigate if the hypothesis of statistical self-similarity in the RSN model is supported by data on a set of 30 basins located across the continental United States that encompass a wide range of hydroclimatic variability. We demonstrate that the generators of the RSN model obey a geometric distribution, and self-similarity holds in a statistical sense in 26 of these 30 basins. The parameters describing the distribution of interior and exterior generators are tested to be statistically different and the difference is shown to produce the well-known Hack's law. The inter-basin variability of RSN parameters is found to be statistically significant. We also test generator dependence on two climatic indices, mean annual precipitation and radiative index of dryness. Some indication of climatic influence on the generators is detected, but this influence is not statistically significant with the sample size available. Finally, two key applications of the RSN model to hydrology and geomorphology are briefly discussed.

40 CFR Appendix Xviii to Part 86 - Statistical Outlier Identification Procedure for Light-Duty Vehicles and Light Light-Duty Trucks...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Statistical Outlier Identification... (CONTINUED) Pt. 86, App. XVIII Appendix XVIII to Part 86—Statistical Outlier Identification Procedure for..., but suffer theoretical deficiencies if statistical significance tests are required. Consequently, the...

40 CFR Appendix Xviii to Part 86 - Statistical Outlier Identification Procedure for Light-Duty Vehicles and Light Light-Duty Trucks...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Statistical Outlier Identification... (CONTINUED) Pt. 86, App. XVIII Appendix XVIII to Part 86—Statistical Outlier Identification Procedure for..., but suffer theoretical deficiencies if statistical significance tests are required. Consequently, the...

Bayesian Methods for Determining the Importance of Effects

USDA-ARS?s Scientific Manuscript database

Criticisms have plagued the frequentist null-hypothesis significance testing (NHST) procedure since the day it was created from the Fisher Significance Test and Hypothesis Test of Jerzy Neyman and Egon Pearson. Alternatives to NHST exist in frequentist statistics, but competing methods are also avai...

Evaluation of gloss changes of two denture acrylic resin materials in four different beverages.

PubMed

Keyf, Filiz; Etikan, Ilker

2004-03-01

The primary disadvantages of the materials which are used in construction of complete and removable partial dentures is that their esthetic, physical and mechanical properties change rapidly with time in the oral environment. For esthetics, color stability is one of the criteria that needs careful attention. Color may provide important information on the serviceability of these materials. Color change affects the gloss of these materials. The objective of the present study was to determine the gloss changes resulting from the testing process in four different beverages in one heat-polymerized denture base resin and one cold-polymerized denture base repair resin. Thirty-six samples were fabricated for each material. Each sample had a smooth polished and a rough unpolished surface. The gloss measurements were made with a glossmeter before testing. Four different beverages (tea, coffee, cola and cherry juice) were used for testing. Two angles of illumination (20 and 60 degrees) were used for the gloss measurements. The samples were immersed in water, tea, coffee, cola and cherry juice solutions. The gloss of the samples was measured again with the glossmeter at the end of the 45th day and 135th day of testing. The arithmetic mean and standard deviation of each of the samples were calculated and compared with each other statistically by using the Wilcoxon test (within times) (p < or = 0.05 significant), the Kruskal-Wallis analysis of variance (p < or = 0.05 significant) and the Mann-Whitney U-test with Bonforoni correction (when the difference between the samples was significant) (p < or = 0.05 significant). The results of this study revealed that gloss changes occurred after testing in heat-polymerized denture base resin and cold-polymerized denture base repair resin. The significance of the gloss changes exhibited by each sample, kept for different lengths of time in the same solution, were compared using the Wilcoxon test. The results were statistically significant (p < or = 0.05). According to the Kruskal-Wallis analysis of variance, the difference between measurements for angles of illumination was statistically significant (p < or = 0.05). Also according to the Mann-Whitney U-test, the difference between two polished surfaces or two unpolished surfaces was statistically insignificant (p > 0.05), but the difference between smooth polished and rough unpolished surfaces was statistically significant (p < or = 0.05). It was found that either the gloss of heat-polymerized denture base resin or the gloss of cold-polymerized denture base repair resin was affected by tested agents, and the four beverages demonstrated noticeable gloss changes. Cherry juice demonstrated the least change, while tea exhibited the greatest change.

The chi-square test of independence.

PubMed

McHugh, Mary L

2013-01-01

The Chi-square statistic is a non-parametric (distribution free) tool designed to analyze group differences when the dependent variable is measured at a nominal level. Like all non-parametric statistics, the Chi-square is robust with respect to the distribution of the data. Specifically, it does not require equality of variances among the study groups or homoscedasticity in the data. It permits evaluation of both dichotomous independent variables, and of multiple group studies. Unlike many other non-parametric and some parametric statistics, the calculations needed to compute the Chi-square provide considerable information about how each of the groups performed in the study. This richness of detail allows the researcher to understand the results and thus to derive more detailed information from this statistic than from many others. The Chi-square is a significance statistic, and should be followed with a strength statistic. The Cramer's V is the most common strength test used to test the data when a significant Chi-square result has been obtained. Advantages of the Chi-square include its robustness with respect to distribution of the data, its ease of computation, the detailed information that can be derived from the test, its use in studies for which parametric assumptions cannot be met, and its flexibility in handling data from both two group and multiple group studies. Limitations include its sample size requirements, difficulty of interpretation when there are large numbers of categories (20 or more) in the independent or dependent variables, and tendency of the Cramer's V to produce relative low correlation measures, even for highly significant results.

Data-driven inference for the spatial scan statistic.

PubMed

Almeida, Alexandre C L; Duarte, Anderson R; Duczmal, Luiz H; Oliveira, Fernando L P; Takahashi, Ricardo H C

2011-08-02

Kulldorff's spatial scan statistic for aggregated area maps searches for clusters of cases without specifying their size (number of areas) or geographic location in advance. Their statistical significance is tested while adjusting for the multiple testing inherent in such a procedure. However, as is shown in this work, this adjustment is not done in an even manner for all possible cluster sizes. A modification is proposed to the usual inference test of the spatial scan statistic, incorporating additional information about the size of the most likely cluster found. A new interpretation of the results of the spatial scan statistic is done, posing a modified inference question: what is the probability that the null hypothesis is rejected for the original observed cases map with a most likely cluster of size k, taking into account only those most likely clusters of size k found under null hypothesis for comparison? This question is especially important when the p-value computed by the usual inference process is near the alpha significance level, regarding the correctness of the decision based in this inference. A practical procedure is provided to make more accurate inferences about the most likely cluster found by the spatial scan statistic.

Immersive Theater - a Proven Way to Enhance Learning Retention

NASA Astrophysics Data System (ADS)

Reiff, P. H.; Zimmerman, L.; Spillane, S.; Sumners, C.

2014-12-01

The portable immersive theater has gone from our first demonstration at fall AGU 2003 to a product offered by multiple companies in various versions to literally millions of users per year. As part of our NASA funded outreach program, we conducted a test of learning in a portable Discovery Dome as contrasted with learning the same materials (visuals and sound track) on a computer screen. We tested 200 middle school students (primarily underserved minorities). Paired t-tests and an independent t-test were used to compare the amount of learning that students achieved. Interest questionnaires were administered to participants in formal (public school) settings and focus groups were conducted in informal (museum camp and educational festival) settings. Overall results from the informal and formal educational setting indicated that there was a statistically significant increase in test scores after viewing We Choose Space. There was a statistically significant increase in test scores for students who viewed We Choose Space in the portable Discovery Dome (9.75) as well as with the computer (8.88). However, long-term retention of the material tested on the questionnaire indicated that for students who watched We Choose Space in the portable Discovery Dome, there was a statistically significant long-term increase in test scores (10.47), whereas, six weeks after learning on the computer, the improvements over the initial baseline (3.49) were far less and were not statistically significant. The test score improvement six weeks after learning in the dome was essentially the same as the post test immediately after watching the show, demonstrating virtually no loss of gained information in the six week interval. In the formal educational setting, approximately 34% of the respondents indicated that they wanted to learn more about becoming a scientist, while 35% expressed an interest in a career in space science. In the informal setting, 26% indicated that they were interested in pursuing a career in space science.

Comparative Analysis of Serum (Anti)oxidative Status Parameters in Healthy Persons

PubMed Central

Jansen, Eugène HJM; Ruskovska, Tatjana

2013-01-01

Five antioxidant and two oxidative stress assays were applied to serum samples of 43 healthy males. The antioxidant tests showed different inter-assay correlations. A very good correlation of 0.807 was observed between the ferric reducing ability of plasma (FRAP) and total antioxidant status (TAS) assay and also a fair correlation of 0.501 between the biological antioxidant potential (BAP) and TAS assay. There was no statistically significant correlation between the BAP and FRAP assay. The anti-oxidant assays have a high correlation with uric acid, especially the TAS (0.922) and FRAP assay (0.869). The BAP assay has a much lower and no statistically significant correlation with uric acid (0.302), which makes BAP more suitable for the antioxidant status. The total thiol assay showed no statistically significant correlation with uric acid (0.114). The total thiol assay, which is based on a completely different principle, showed a good and statistically significant correlation with the BAP assay (0.510) and also to the TAS assay, but to a lower and not significant extent (0.279) and not with the FRAP assay (−0.008). The oxy-adsorbent test (OXY) assay has no correlation with any of the other assays tested. The oxidative stress assays, reactive oxygen metabolites (ROM) and total oxidant status (TOS), based on a different principle, do not show a statistically significant correlation with the serum samples in this study. Both assays showed a negative, but not significant, correlation with the antioxidant assays. In conclusion, the ROM, TOS, BAP and TTP assays are based on different principles and will have an additional value when a combination of these assays will be applied in large-scale population studies. PMID:23507749

How many spectral lines are statistically significant?

NASA Astrophysics Data System (ADS)

Freund, J.

When experimental line spectra are fitted with least squares techniques one frequently does not know whether n or n + 1 lines may be fitted safely. This paper shows how an F-test can be applied in order to determine the statistical significance of including an extra line into the fitting routine.

Research design and statistical methods in Pakistan Journal of Medical Sciences (PJMS)

PubMed Central

Akhtar, Sohail; Shah, Syed Wadood Ali; Rafiq, M.; Khan, Ajmal

2016-01-01

Objective: This article compares the study design and statistical methods used in 2005, 2010 and 2015 of Pakistan Journal of Medical Sciences (PJMS). Methods: Only original articles of PJMS were considered for the analysis. The articles were carefully reviewed for statistical methods and designs, and then recorded accordingly. The frequency of each statistical method and research design was estimated and compared with previous years. Results: A total of 429 articles were evaluated (n=74 in 2005, n=179 in 2010, n=176 in 2015) in which 171 (40%) were cross-sectional and 116 (27%) were prospective study designs. A verity of statistical methods were found in the analysis. The most frequent methods include: descriptive statistics (n=315, 73.4%), chi-square/Fisher’s exact tests (n=205, 47.8%) and student t-test (n=186, 43.4%). There was a significant increase in the use of statistical methods over time period: t-test, chi-square/Fisher’s exact test, logistic regression, epidemiological statistics, and non-parametric tests. Conclusion: This study shows that a diverse variety of statistical methods have been used in the research articles of PJMS and frequency improved from 2005 to 2015. However, descriptive statistics was the most frequent method of statistical analysis in the published articles while cross-sectional study design was common study design. PMID:27022365

Evaluating collective significance of climatic trends: A comparison of methods on synthetic data

NASA Astrophysics Data System (ADS)

Huth, Radan; Dubrovský, Martin

2017-04-01

The common approach to determine whether climatic trends are significantly different from zero is to conduct individual (local) tests at each single site (station or gridpoint). Whether the number of sites where the trends are significantly non-zero can or cannot occur by random, is almost never evaluated in trend studies. That is, collective (global) significance of trends is ignored. We compare three approaches to evaluating collective statistical significance of trends at a network of sites, using the following statistics: (i) the number of successful local tests (a successful test means here a test in which the null hypothesis of no trend is rejected); this is a standard way of assessing collective significance in various applications in atmospheric sciences; (ii) the smallest p-value among the local tests (Walker test); and (iii) the counts of positive and negative trends regardless of their magnitudes and local significance. The third approach is a new procedure that we propose; the rationale behind it is that it is reasonable to assume that the prevalence of one sign of trends at individual sites is indicative of a high confidence in the trend not being zero, regardless of the (in)significance of individual local trends. A potentially large amount of information contained in trends that are not locally significant, which are typically deemed irrelevant and neglected, is thus not lost and is retained in the analysis. In this contribution we examine the feasibility of the proposed way of significance testing on synthetic data, produced by a multi-site stochastic generator, and compare it with the two other ways of assessing collective significance, which are well established now. The synthetic dataset, mimicking annual mean temperature on an array of stations (or gridpoints), is constructed assuming a given statistical structure characterized by (i) spatial separation (density of the station network), (ii) local variance, (iii) temporal and spatial autocorrelations, and (iv) the trend magnitude. The probabilistic distributions of the three test statistics (null distributions) and critical values of the tests are determined from multiple realizations of the synthetic dataset, in which no trend is imposed at each site (that is, any trend is a result of random fluctuations only). The procedure is then evaluated by determining the type II error (the probability of a false detection of a trend) in the presence of a trend with a known magnitude, for which the synthetic dataset with an imposed spatially uniform non-zero trend is used. A sensitivity analysis is conducted for various combinations of the trend magnitude and spatial autocorrelation.

Cognitive predictors of balance in Parkinson's disease.

PubMed

Fernandes, Ângela; Mendes, Andreia; Rocha, Nuno; Tavares, João Manuel R S

2016-06-01

Postural instability is one of the most incapacitating symptoms of Parkinson's disease (PD) and appears to be related to cognitive deficits. This study aims to determine the cognitive factors that can predict deficits in static and dynamic balance in individuals with PD. A sociodemographic questionnaire characterized 52 individuals with PD for this work. The Trail Making Test, Rule Shift Cards Test, and Digit Span Test assessed the executive functions. The static balance was assessed using a plantar pressure platform, and dynamic balance was based on the Timed Up and Go Test. The results were statistically analysed using SPSS Statistics software through linear regression analysis. The results show that a statistically significant model based on cognitive outcomes was able to explain the variance of motor variables. Also, the explanatory value of the model tended to increase with the addition of individual and clinical variables, although the resulting model was not statistically significant The model explained 25-29% of the variability of the Timed Up and Go Test, while for the anteroposterior displacement it was 23-34%, and for the mediolateral displacement it was 24-39%. From the findings, we conclude that the cognitive performance, especially the executive functions, is a predictor of balance deficit in individuals with PD.

Statistical model specification and power: recommendations on the use of test-qualified pooling in analysis of experimental data

PubMed Central

Colegrave, Nick

2017-01-01

A common approach to the analysis of experimental data across much of the biological sciences is test-qualified pooling. Here non-significant terms are dropped from a statistical model, effectively pooling the variation associated with each removed term with the error term used to test hypotheses (or estimate effect sizes). This pooling is only carried out if statistical testing on the basis of applying that data to a previous more complicated model provides motivation for this model simplification; hence the pooling is test-qualified. In pooling, the researcher increases the degrees of freedom of the error term with the aim of increasing statistical power to test their hypotheses of interest. Despite this approach being widely adopted and explicitly recommended by some of the most widely cited statistical textbooks aimed at biologists, here we argue that (except in highly specialized circumstances that we can identify) the hoped-for improvement in statistical power will be small or non-existent, and there is likely to be much reduced reliability of the statistical procedures through deviation of type I error rates from nominal levels. We thus call for greatly reduced use of test-qualified pooling across experimental biology, more careful justification of any use that continues, and a different philosophy for initial selection of statistical models in the light of this change in procedure. PMID:28330912

The effects of academic grouping on student performance in science

NASA Astrophysics Data System (ADS)

Scoggins, Sally Smykla

The current action research study explored how student placement in heterogeneous or homogeneous classes in seventh-grade science affected students' eighth-grade Science State of Texas Assessment of Academic Readiness (STAAR) scores, and how ability grouping affected students' scores based on race and socioeconomic status. The population included all eighth-grade students in the target district who took the regular eighth-grade science STAAR over four academic school years. The researcher ran three statistical tests: a t-test for independent samples, a one-way between subjects analysis of variance (ANOVA) and a two-way between subjects ANOVA. The results showed no statistically significant difference between eighth-grade Pre-AP students from seventh-grade Pre-AP classes and eighth-grade Pre-AP students from heterogeneous seventh-grade classes and no statistically significant difference between Pre-AP students' scores based on socioeconomic status. There was no statistically significant interaction between socioeconomic status and the seventh-grade science classes. The scores between regular eighth-grade students who were in heterogeneous seventh-grade classes were statistically significantly higher than the scores of regular eighth-grade students who were in regular seventh-grade classes. The results also revealed that the scores of students who were White were statistically significantly higher than the scores of students who were Black and Hispanic. Black and Hispanic scores did not differ significantly. Further results indicated that the STAAR Level II and Level III scores were statistically significantly higher for the Pre-AP eighth-grade students who were in heterogeneous seventh-grade classes than the STAAR Level II and Level III scores of Pre-AP eighth-grade students who were in Pre-AP seventh-grade classes.

The effects of compensatory workplace exercises to reduce work-related stress and musculoskeletal pain1

PubMed Central

de Freitas-Swerts, Fabiana Cristina Taubert; Robazzi, Maria Lúcia do Carmo Cruz

2014-01-01

OBJECTIVES: to assess the effect of a compensatory workplace exercise program on workers with the purpose of reducing work-related stress and musculoskeletal pain. METHOD: quasi-experimental research with quantitative analysis of the data, involving 30 administrative workers from a Higher Education Public Institution. For data collection, questionnaires were used to characterize the workers, as well as the Workplace Stress Scale and the Corlett Diagram. The research took place in three stages: first: pre-test with the application of the questionnaires to the subjects; second: Workplace Exercise taking place twice a week, for 15 minutes, during a period of 10 weeks; third: post-test in which the subjects answered the questionnaires again. For data analysis, the descriptive statistics and non-parametric statistics were used through the Wilcoxon Test. RESULTS: work-related stress was present in the assessed workers, but there was no statistically significant reduction in the scores after undergoing Workplace Exercise. However, there was a statistically significant pain reduction in the neck, cervical, upper, middle and lower back, right thigh, left leg, right ankle and feet. CONCLUSION: the Workplace Exercise promoted a significant pain reduction in the spine, but did not result in a significant reduction in the levels of work-related stress. PMID:25296147

Why Current Statistics of Complementary Alternative Medicine Clinical Trials is Invalid.

PubMed

Pandolfi, Maurizio; Carreras, Giulia

2018-06-07

It is not sufficiently known that frequentist statistics cannot provide direct information on the probability that the research hypothesis tested is correct. The error resulting from this misunderstanding is compounded when the hypotheses under scrutiny have precarious scientific bases, which, generally, those of complementary alternative medicine (CAM) are. In such cases, it is mandatory to use inferential statistics, considering the prior probability that the hypothesis tested is true, such as the Bayesian statistics. The authors show that, under such circumstances, no real statistical significance can be achieved in CAM clinical trials. In this respect, CAM trials involving human material are also hardly defensible from an ethical viewpoint.

Evaluation of Evidence of Statistical Support and Corroboration of Subgroup Claims in Randomized Clinical Trials.

PubMed

Wallach, Joshua D; Sullivan, Patrick G; Trepanowski, John F; Sainani, Kristin L; Steyerberg, Ewout W; Ioannidis, John P A

2017-04-01

Many published randomized clinical trials (RCTs) make claims for subgroup differences. To evaluate how often subgroup claims reported in the abstracts of RCTs are actually supported by statistical evidence (P < .05 from an interaction test) and corroborated by subsequent RCTs and meta-analyses. This meta-epidemiological survey examines data sets of trials with at least 1 subgroup claim, including Subgroup Analysis of Trials Is Rarely Easy (SATIRE) articles and Discontinuation of Randomized Trials (DISCO) articles. We used Scopus (updated July 2016) to search for English-language articles citing each of the eligible index articles with at least 1 subgroup finding in the abstract. Articles with a subgroup claim in the abstract with or without evidence of statistical heterogeneity (P < .05 from an interaction test) in the text and articles attempting to corroborate the subgroup findings. Study characteristics of trials with at least 1 subgroup claim in the abstract were recorded. Two reviewers extracted the data necessary to calculate subgroup-level effect sizes, standard errors, and the P values for interaction. For individual RCTs and meta-analyses that attempted to corroborate the subgroup findings from the index articles, trial characteristics were extracted. Cochran Q test was used to reevaluate heterogeneity with the data from all available trials. The number of subgroup claims in the abstracts of RCTs, the number of subgroup claims in the abstracts of RCTs with statistical support (subgroup findings), and the number of subgroup findings corroborated by subsequent RCTs and meta-analyses. Sixty-four eligible RCTs made a total of 117 subgroup claims in their abstracts. Of these 117 claims, only 46 (39.3%) in 33 articles had evidence of statistically significant heterogeneity from a test for interaction. In addition, out of these 46 subgroup findings, only 16 (34.8%) ensured balance between randomization groups within the subgroups (eg, through stratified randomization), 13 (28.3%) entailed a prespecified subgroup analysis, and 1 (2.2%) was adjusted for multiple testing. Only 5 (10.9%) of the 46 subgroup findings had at least 1 subsequent pure corroboration attempt by a meta-analysis or an RCT. In all 5 cases, the corroboration attempts found no evidence of a statistically significant subgroup effect. In addition, all effect sizes from meta-analyses were attenuated toward the null. A minority of subgroup claims made in the abstracts of RCTs are supported by their own data (ie, a significant interaction effect). For those that have statistical support (P < .05 from an interaction test), most fail to meet other best practices for subgroup tests, including prespecification, stratified randomization, and adjustment for multiple testing. Attempts to corroborate statistically significant subgroup differences are rare; when done, the initially observed subgroup differences are not reproduced.

Evidence-based practice knowledge, attitudes, and practice of online graduate nursing students.

PubMed

Rojjanasrirat, Wilaiporn; Rice, Jan

2017-06-01

This study aimed to evaluate changes in evidence-based practice (EBP) knowledge, attitudes, and practice of nursing students before and after completing an online, graduate level, introductory research/EBP course. A prospective one-group pretest-posttest design. A private university in the Midwestern, USA. Sixty-three online nurse practitioner students in Master's program. A convenient sample of online graduate nursing students who enrolled in the research/EBP course was invited to participate in the study. Study outcomes were measured using the Evidence-Based Practice Questionnaire (EBPQ) before and after completing the course. Descriptive statistics and paired-Samples t-test was used to assess the mean differences between pre-and post-test scores. Overall, students' post-test EBP scores were significantly improved over pre-test scores, t(63)=-9.034, p<0.001). Statistically significant differences were found for practice of EBP mean scores t(63)=-12.78, p=0.001). No significant differences were found between pre and post-tests on knowledge and attitudes toward EBP scores. Most frequently cited barriers to EBP were lack of understanding of statistics, interpretation of findings, lack of time, and lack of library resources. Copyright © 2017 Elsevier Ltd. All rights reserved.

Initial Experience with Balloon-Occluded Trans-catheter Arterial Chemoembolization (B-TACE) for Hepatocellular Carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maruyama, Mitsunari, E-mail: mitunari@med-shimane.u.ac.jp; Yoshizako, Takeshi, E-mail: yosizako@med.shimane-u.ac.jp; Nakamura, Tomonori, E-mail: t-naka@med.shimane-u.ac.jp

2016-03-15

PurposeThis study was performed to evaluate the accumulation of lipiodol emulsion (LE) and adverse events during our initial experience of balloon-occluded trans-catheter arterial chemoembolization (B-TACE) for hepatocellular carcinoma (HCC) compared with conventional TACE (C-TACE).MethodsB-TACE group (50 cases) was compared with C-TACE group (50 cases). The ratio of the LE concentration in the tumor to that in the surrounding embolized liver parenchyma (LE ratio) was calculated after each treatment. Adverse events were evaluated according to the Common Terminology Criteria for Adverse Effects (CTCAE) version 4.0.ResultsThe LE ratio at the level of subsegmental showed a statistically significant difference between the groups (tmore » test: P < 0.05). Only elevation of alanine aminotransferase was more frequent in the B-TACE group, showing a statistically significant difference (Mann–Whitney test: P < 0.05). While B-TACE caused severe adverse events (liver abscess and infarction) in patients with bile duct dilatation, there was no statistically significant difference in incidence between the groups. Multivariate logistic regression analysis suggested that the significant risk factor for liver abscess/infarction was bile duct dilatation (P < 0.05).ConclusionThe LE ratio at the level of subsegmental showed a statistically significant difference between the groups (t test: P < 0.05). B-TACE caused severe adverse events (liver abscess and infarction) in patients with bile duct dilatation.« less

Visual-Motor Test Performance: Race and Achievement Variables.

ERIC Educational Resources Information Center

Fuller, Gerald B.; Friedrich, Douglas

1979-01-01

Rural Black and White children of variant academic achievement were tested on the Minnesota Percepto-Diagnostic Test, which consists of six gestalt designs for the subject to copy. Analyses resulted only in a significant achievement effect; when intellectual level was statistically controlled, race was not a significant variable. (Editor/SJL)

Statistics Using Just One Formula

ERIC Educational Resources Information Center

Rosenthal, Jeffrey S.

2018-01-01

This article advocates that introductory statistics be taught by basing all calculations on a single simple margin-of-error formula and deriving all of the standard introductory statistical concepts (confidence intervals, significance tests, comparisons of means and proportions, etc) from that one formula. It is argued that this approach will…

Statistical comparison of pooled nitrogen washout data of various altitude decompression response groups

NASA Technical Reports Server (NTRS)

Edwards, B. F.; Waligora, J. M.; Horrigan, D. J., Jr.

1985-01-01

This analysis was done to determine whether various decompression response groups could be characterized by the pooled nitrogen (N2) washout profiles of the group members, pooling individual washout profiles provided a smooth time dependent function of means representative of the decompression response group. No statistically significant differences were detected. The statistical comparisons of the profiles were performed by means of univariate weighted t-test at each 5 minute profile point, and with levels of significance of 5 and 10 percent. The estimated powers of the tests (i.e., probabilities) to detect the observed differences in the pooled profiles were of the order of 8 to 30 percent.

A scan statistic for binary outcome based on hypergeometric probability model, with an application to detecting spatial clusters of Japanese encephalitis.

PubMed

Zhao, Xing; Zhou, Xiao-Hua; Feng, Zijian; Guo, Pengfei; He, Hongyan; Zhang, Tao; Duan, Lei; Li, Xiaosong

2013-01-01

As a useful tool for geographical cluster detection of events, the spatial scan statistic is widely applied in many fields and plays an increasingly important role. The classic version of the spatial scan statistic for the binary outcome is developed by Kulldorff, based on the Bernoulli or the Poisson probability model. In this paper, we apply the Hypergeometric probability model to construct the likelihood function under the null hypothesis. Compared with existing methods, the likelihood function under the null hypothesis is an alternative and indirect method to identify the potential cluster, and the test statistic is the extreme value of the likelihood function. Similar with Kulldorff's methods, we adopt Monte Carlo test for the test of significance. Both methods are applied for detecting spatial clusters of Japanese encephalitis in Sichuan province, China, in 2009, and the detected clusters are identical. Through a simulation to independent benchmark data, it is indicated that the test statistic based on the Hypergeometric model outweighs Kulldorff's statistics for clusters of high population density or large size; otherwise Kulldorff's statistics are superior.

Evaluation of conventional, protaper hand and protaper rotary instrumentation system for apical extrusion of debris, irrigants and bacteria- An in vitro randomized trial

PubMed Central

Kalra, Pinky; Suman, Ethel; Shenoy, Ramya; Suprabha, Baranya-Shrikrishna

2017-01-01

Background Endodontic instrumentation carries the risk of over extrusion of debris and bacteria. The technique used and the type of instrumentation influences this risk. Aim The purpose of this study was to evaluate and compare the K-file, ProTaper hand and ProTaper rotary instrumentation systems for the amount of apically extruded debris, irrigant solution and intracanal bacteria. Design Experimental single blinded randomized type of in vitro study with sample of 30 single rooted teeth. Endodontic access cavities were prepared and the root canals were filled with the suspension of E. faecalis. Myers and Montogomery Model was used to collect apically extruded debris and irrigant. Canals were prepared using K files, Hand protapers and Protaper rotary files. Statistical analysis Non Parametric test like Kruskal-Wallis and Mann-Whitney U test were applied to determine the significant differences among the group. Results Tests revealed statistically significant difference between the amount of debris and number of bacteria extruded by the ProTaper hand and the K-files. No statistically significant difference was observed between the amounts of irrigant extruded by the ProTaper hand and the K-file system. Statistically significant differences were observed between the amounts of bacteria and irrigant extruded by the ProTaper rotary and the Protaper hand. No statistically significant difference was observed between the amounts of debris extruded by the ProTaper hand and the K-file system. Conclusions Amount of apical extrusion of irrigant solution, bacteria and debris are significantly greater with K File instruments and least with Protaper rotary instruments. Key words:Protaper, rotary, periapical extrusion. PMID:28210445

Eruption patterns of the chilean volcanoes Villarrica, Llaima, and Tupungatito

NASA Astrophysics Data System (ADS)

Muñoz, Miguel

1983-09-01

The historical eruption records of three Chilean volcanoes have been subjected to many statistical tests, and none have been found to differ significantly from random, or Poissonian, behaviour. The statistical analysis shows rough conformity with the descriptions determined from the eruption rate functions. It is possible that a constant eruption rate describes the activity of Villarrica; Llaima and Tupungatito present complex eruption rate patterns that appear, however, to have no statistical significance. Questions related to loading and extinction processes and to the existence of shallow secondary magma chambers to which magma is supplied from a deeper system are also addressed. The analysis and the computation of the serial correlation coefficients indicate that the three series may be regarded as stationary renewal processes. None of the test statistics indicates rejection of the Poisson hypothesis at a level less than 5%, but the coefficient of variation for the eruption series at Llaima is significantly different from the value expected for a Poisson process. Also, the estimates of the normalized spectrum of the counting process for the three series suggest a departure from the random model, but the deviations are not found to be significant at the 5% level. Kolmogorov-Smirnov and chi-squared test statistics, applied directly to ascertaining to which probability P the random Poisson model fits the data, indicate that there is significant agreement in the case of Villarrica ( P=0.59) and Tupungatito ( P=0.3). Even though the P-value for Llaima is a marginally significant 0.1 (which is equivalent to rejecting the Poisson model at the 90% confidence level), the series suggests that nonrandom features are possibly present in the eruptive activity of this volcano.

Statistical Significance and Effect Size: Two Sides of a Coin.

ERIC Educational Resources Information Center

Fan, Xitao

This paper suggests that statistical significance testing and effect size are two sides of the same coin; they complement each other, but do not substitute for one another. Good research practice requires that both should be taken into consideration to make sound quantitative decisions. A Monte Carlo simulation experiment was conducted, and a…

Using the Descriptive Bootstrap to Evaluate Result Replicability (Because Statistical Significance Doesn't)

ERIC Educational Resources Information Center

Spinella, Sarah

2011-01-01

As result replicability is essential to science and difficult to achieve through external replicability, the present paper notes the insufficiency of null hypothesis statistical significance testing (NHSST) and explains the bootstrap as a plausible alternative, with a heuristic example to illustrate the bootstrap method. The bootstrap relies on…

The Development and Demonstration of Multiple Regression Models for Operant Conditioning Questions.

ERIC Educational Resources Information Center

Fanning, Fred; Newman, Isadore

Based on the assumption that inferential statistics can make the operant conditioner more sensitive to possible significant relationships, regressions models were developed to test the statistical significance between slopes and Y intercepts of the experimental and control group subjects. These results were then compared to the traditional operant…

Factors related to student performance in statistics courses in Lebanon

NASA Astrophysics Data System (ADS)

Naccache, Hiba Salim

The purpose of the present study was to identify factors that may contribute to business students in Lebanese universities having difficulty in introductory and advanced statistics courses. Two statistics courses are required for business majors at Lebanese universities. Students are not obliged to be enrolled in any math courses prior to taking statistics courses. Drawing on recent educational research, this dissertation attempted to identify the relationship between (1) students’ scores on Lebanese university math admissions tests; (2) students’ scores on a test of very basic mathematical concepts; (3) students’ scores on the survey of attitude toward statistics (SATS); (4) course performance as measured by students’ final scores in the course; and (5) their scores on the final exam. Data were collected from 561 students enrolled in multiple sections of two courses: 307 students in the introductory statistics course and 260 in the advanced statistics course in seven campuses across Lebanon over one semester. The multiple regressions results revealed four significant relationships at the introductory level: between students’ scores on the math quiz with their (1) final exam scores; (2) their final averages; (3) the Cognitive subscale of the SATS with their final exam scores; and (4) their final averages. These four significant relationships were also found at the advanced level. In addition, two more significant relationships were found between students’ final average and the two subscales of Effort (5) and Affect (6). No relationship was found between students’ scores on the admission math tests and both their final exam scores and their final averages in both the introductory and advanced level courses. On the other hand, there was no relationship between students’ scores on Lebanese admissions tests and their final achievement. Although these results were consistent across course formats and instructors, they may encourage Lebanese universities to assess the effectiveness of prerequisite math courses. Moreover, these findings may lead the Lebanese Ministry of Education to make changes to the admissions exams, course prerequisites, and course content. Finally, to enhance the attitude of students, new learning techniques, such as group work during class meetings can be helpful, and future research should aim to test the effectiveness of these pedagogical techniques on students’ attitudes toward statistics.

Statistical analysis for validating ACO-KNN algorithm as feature selection in sentiment analysis

NASA Astrophysics Data System (ADS)

Ahmad, Siti Rohaidah; Yusop, Nurhafizah Moziyana Mohd; Bakar, Azuraliza Abu; Yaakub, Mohd Ridzwan

2017-10-01

This research paper aims to propose a hybrid of ant colony optimization (ACO) and k-nearest neighbor (KNN) algorithms as feature selections for selecting and choosing relevant features from customer review datasets. Information gain (IG), genetic algorithm (GA), and rough set attribute reduction (RSAR) were used as baseline algorithms in a performance comparison with the proposed algorithm. This paper will also discuss the significance test, which was used to evaluate the performance differences between the ACO-KNN, IG-GA, and IG-RSAR algorithms. This study evaluated the performance of the ACO-KNN algorithm using precision, recall, and F-score, which were validated using the parametric statistical significance tests. The evaluation process has statistically proven that this ACO-KNN algorithm has been significantly improved compared to the baseline algorithms. The evaluation process has statistically proven that this ACO-KNN algorithm has been significantly improved compared to the baseline algorithms. In addition, the experimental results have proven that the ACO-KNN can be used as a feature selection technique in sentiment analysis to obtain quality, optimal feature subset that can represent the actual data in customer review data.

Effectiveness of groundwater governance structures and institutions in Tanzania

NASA Astrophysics Data System (ADS)

Gudaga, J. L.; Kabote, S. J.; Tarimo, A. K. P. R.; Mosha, D. B.; Kashaigili, J. J.

2018-05-01

This paper examines effectiveness of groundwater governance structures and institutions in Mbarali District, Mbeya Region. The paper adopts exploratory sequential research design to collect quantitative and qualitative data. A random sample of 90 groundwater users with 50% women was involved in the survey. Descriptive statistics, Kruskal-Wallis H test and Mann-Whitney U test were used to compare the differences in responses between groups, while qualitative data were subjected to content analysis. The results show that the Village Councils and Community Water Supply Organizations (COWSOs) were effective in governing groundwater. The results also show statistical significant difference on the overall extent of effectiveness of the Village Councils in governing groundwater between villages ( P = 0.0001), yet there was no significant difference ( P > 0.05) between male and female responses on the effectiveness of Village Councils, village water committees and COWSOs. The Mann-Whitney U test showed statistical significant difference between male and female responses on effectiveness of formal and informal institutions ( P = 0.0001), such that informal institutions were effective relative to formal institutions. The Kruskal-Wallis H test also showed statistical significant difference ( P ≤ 0.05) on the extent of effectiveness of formal institutions, norms and values between low, medium and high categories. The paper concludes that COWSOs were more effective in governing groundwater than other groundwater governance structures. Similarly, norms and values were more effective than formal institutions. The paper recommends sensitization and awareness creation on formal institutions so that they can influence water users' behaviour to govern groundwater.

Definition of simulated driving tests for the evaluation of drivers' reactions and responses.

PubMed

Bartolozzi, Riccardo; Frendo, Francesco

2014-01-01

This article aims at identifying the most significant measures in 2 perception-response (PR) tests performed at a driving simulator: a braking test and a lateral skid test, which were developed in this work. Forty-eight subjects (26 females and 22 males) with a mean age of 24.9 ± 3.0 years were enrolled for this study. They were asked to perform a drive on the driving simulator at the University of Pisa (Italy) following a specific test protocol, including 8-10 braking tests and 8-10 lateral skid tests. Driver input signals and vehicle model signals were recorded during the drives and analyzed to extract measures such as the reaction time, first response time, etc. Following a statistical procedure (based on analysis of variance [ANOVA] and post hoc tests), all test measures (3 for the braking test and 8 for the lateral skid test) were analyzed in terms of statistically significant differences among different drivers. The presented procedure allows evaluation of the capability of a given test to distinguish among different drivers. In the braking test, the reaction time showed a high dispersion among single drivers, leading to just 4.8 percent of statistically significant driver pairs (using the Games-Howell post hoc test), whereas the pedal transition time scored 31.9 percent. In the lateral skid test, 28.5 percent of the 2 × 2 comparisons showed significantly different reaction times, 19.5 percent had different response times, 35.2 percent had a different second peak of the steering wheel signal, and 33 percent showed different values of the integral of the steering wheel signal. For the braking test, which has been widely employed in similar forms in the literature, it was shown how the reaction time, with respect to the pedal transition time, can have a higher dispersion due to the influence of external factors. For the lateral skid test, the following measures were identified as the most significant for application studies: the reaction time for the reaction phase, the second peak of the steering wheel angle for the first instinctive response, and the integral of the steering wheel angle for the complete response. The methodology used to analyze the test measures was founded on statistically based and objective evaluation criteria and could be applied to other tests. Even if obtained with a fixed-base simulator, the obtained results represent useful information for applications of the presented PR tests in experimental campaigns with driving simulators.

NASA Rat Acoustic Tolerance Test 1994-1995: 8 kHz, 16 kHz, 32 kHz Experiments

NASA Technical Reports Server (NTRS)

Mele, Gary D.; Holley, Daniel C.; Naidu, Sujata

1996-01-01

Adult male Sprague-Dawley rats were exposed to chronic applied sound (74 to 79 dB, SPL) with octave band center frequencies of either 8, 16 or 32 kHz for up to 60 days. Control cages had ambient sound levels of about 62 dB (SPL). Groups of rats (test vs. control; N=9 per group) were euthanized after 0. 5. 14, 30, and 60 days. On each euthanasia day, objective evaluation of their physiology and behavior was performed using a Stress Assessment Battery (SAB) of measures. In addition, rat hearing was assessed using the brain stem auditory evoked potential (BAER) method after 60 days of exposure. No statistically significant differences in mean daily food use could be attributed to the presence of the applied test sound. Test rats used 5% more water than control rats. In the 8 kHz and 32 kHz tests this amount was statistically significant(P less than .05). This is a minor difference of questionable physiological significance. However, it may be an indication of a small reaction to the constant applied sound. Across all test frequencies, day 5 test rats had 6% larger spleens than control rats. No other body or organ weight differences were found to be statistically significant with respect to the application of sound. This spleen effect may be a transient adaptive process related to adaptation to the constant applied noise. No significant test effect on differential white blood cell counts could be demonstrated. One group demonstrated a low eosinophil count (16 kHz experiment, day 14 test group). However this was highly suspect. Across all test frequencies studied, day 5 test rats had 17% fewer total leukocytes than day 5 control rats. Sound exposed test rats exhibited 44% lower plasma corticosterone concentrations than did control rats. Note that the plasma corticosterone concentration was lower in the sound exposed test animals than the control animals in every instance (frequency exposure and number of days exposed).

Improved method for selection of the NOAEL.

PubMed

Calabrese, E J; Baldwin, L A

1994-02-01

The paper proposes that the NOAEL be defined as the highest dosage tested that is statistically significantly different from the control group while also being statistically significantly different from the LOAEL. This new definition requires that the NOAEL be defined from two points of reference rather than the current approach (i.e., single point of reference) in which the NOAEL represents only the highest dosage not statistically significantly different from the control group. This proposal is necessary in order to differentiate NOAELs which are statistically distinguishable from the LOAEL. Under the new regime only those satisfying both criteria would be designated a true NOAEL while those satisfying only one criteria (i.e., not statistically significant different from the control group) would be designated a "quasi" NOAEL and handled differently (i.e., via an uncertainty factor) for risk assessment purposes.

Visualization and statistical comparisons of microbial communities using R packages on Phylochip data.

PubMed

Holmes, Susan; Alekseyenko, Alexander; Timme, Alden; Nelson, Tyrrell; Pasricha, Pankaj Jay; Spormann, Alfred

2011-01-01

This article explains the statistical and computational methodology used to analyze species abundances collected using the LNBL Phylochip in a study of Irritable Bowel Syndrome (IBS) in rats. Some tools already available for the analysis of ordinary microarray data are useful in this type of statistical analysis. For instance in correcting for multiple testing we use Family Wise Error rate control and step-down tests (available in the multtest package). Once the most significant species are chosen we use the hypergeometric tests familiar for testing GO categories to test specific phyla and families. We provide examples of normalization, multivariate projections, batch effect detection and integration of phylogenetic covariation, as well as tree equalization and robustification methods.

Are P values and statistical assessments in poster abstracts presented at annual meetings of Taiwan Society of Anesthesiologists relative to the characteristics of hospitals?

PubMed

Lee, Fu-Jung; Wu, Chih-Cheng; Peng, Shih-Yen; Fan, Kuo-Tung

2007-09-01

Many anesthesiologists in medical centers (MC) or in anesthesiologist-training hospitals (ATH) are accustomed to present their research data in the form of poster abstracts at the annual meetings of Taiwan Society of Anesthesiologists (TSA) to represent their academic gainings in a designated period of time. However, an orphaned P value without mentioning the related specified statistical test has frequently been found in these articles. The difference in presentation of statistical test after P value between MC/ATH and non-MC/non-ATH in recent three TSA consecutive annual meetings was explored in this article. We collected the proceedings handbooks of TSA annual meetings in a period spanning 3 yrs (2003 to 2005) and analyzed the hospital characteristic of first institute-byliner in the poster abstract. Data were analyzed with Fisher's exact test and statistical significance was assumed if P < 0.05. Included were 101 poster abstracts with byliners of 20 hospitals. Only 2 of the 20 hospitals were accredited as non-ATH and 4 as non-MC. There were 64 (63%) abstracts without specified statistical test after P value and no significant difference was found among each category. (P = 0.47 in ATH vs. non-ATH and P = 0.07 in MC vs. non-MC). The basic concept of P value with specified statistical test was not applicable comprehensively in poster abstracts of the annual conferences. Based on our wishful intention, we suggest that the anesthesia administrators and senior anesthesiologists at ATH or MC, and the members of the committee responsible for running academic affairs in TSA, should pay attention to this prodigy and work together to improve our basic statistics in poster presentation.

40 CFR Appendix IV to Part 264 - Cochran's Approximation to the Behrens-Fisher Students' t-test

Code of Federal Regulations, 2011 CFR

2011-07-01

... summary measures to calculate a t-statistic (t*) and a comparison t-statistic (tc). The t* value is compared to the tc value and a conclusion reached as to whether there has been a statistically significant... made in collecting the background data. The t-statistic (tc), against which t* will be compared...

40 CFR Appendix IV to Part 264 - Cochran's Approximation to the Behrens-Fisher Students' t-test

Code of Federal Regulations, 2010 CFR

2010-07-01

... summary measures to calculate a t-statistic (t*) and a comparison t-statistic (tc). The t* value is compared to the tc value and a conclusion reached as to whether there has been a statistically significant... made in collecting the background data. The t-statistic (tc), against which t* will be compared...

Robustness of Multiple Objective Decision Analysis Preference Functions

DTIC Science & Technology

2002-06-01

p p′ : The probability of some event. ,i ip q : The probability of event . i Π : An aggregation of proportional data used in calculating a test ...statistical tests of the significance of the term and also is conducted in a multivariate framework rather than the ROSA univariate approach. A...residual error is ˆ−e = y y (45) The coefficient provides a ready indicator of the contribution for the associated variable and statistical tests

Physical properties and comparative strength of a bioactive luting cement.

PubMed

Jefferies, Steven; Lööf, Jesper; Pameijer, Cornelis H; Boston, Daniel; Galbraith, Colin; Hermansson, Leif

2013-01-01

New dental cement formulations require testing to determine physical and mechanical laboratory properties. To test an experimental calcium aluminate/glass-ionomer cement, Ceramir C and B (CC and B), regarding compressive strength (CS), film thickness (FT), net setting time (ST) and Vickers hardness. An additional test to evaluate potential dimensional change/expansion properties of this cement was also conducted. CS was measured according to a slightly modified ISO 9917:2003 for the CC and B specimens. The samples were not clamped while being exposed to relative humidity of great than 90 percent at 37 degrees C for 10 minutes before being stored in phosphate-buffered saline at 37 degrees C. For the CS, four groups were tested: Group 1-CC and B; Group 2-RelyX Luting Cement; Group 3-Fuji Plus; and Group 4-RelyX Unicem. Samples from all groups were stored for 24 hours before testing. Only CCandB was tested for ST and FT according to ISO 9917:2003. The FT was tested 2 minutes after mixing. Vickers hardness was evaluated using the CSM Microhardness Indentation Tester using zinc phosphate cement as a comparison material. Expansion testing included evaluating potential cracks in feldspathic porcelain jacket crowns (PJCs). The mean and standard deviation after 24 hours were expressed in MPa: Group 1 equals 160 plus or equal to 27; Group 2 equals 96 plus or equal to 10; Group 3 equals 138 plus or equal to 15; Group 4 equals 157 plus or equal to 10. A single-factor ANOVA demonstrated statistically significant differences between the groups (P less than 0.001). Pair-wise statistical comparison demonstrated a statistically significant difference between Groups 1 and 2. No statistically significant differences were found between other groups. The FT was 16.8 plus or equal to 0.9 and the ST was 4.8 plus or equal to 0.1 min. Vickers hardness for Ceramir C and B was 68.3 plus or equal to 17.2 and was statistically significantly higher (P less than 0.05) than Fleck's Zinc Phosphate cement at Vickers hardness of 51.4 plus or equal to 10. There was no evidence of cracks due to radial expansion in PJCs by the Ceramir C and B cement. All luting cements tested demonstrated compressive strengths well in excess of the ISO requirement for water-based cements of no less than 50 MPa. Ceramir C and B showed significantly higher CS than RelyX Luting Cement after 24 hours, but was not significantly higher than either Fuji Plus or RelyX Unicem. The ST and FT values of CC and B conform to and are within the boundaries of the requirements of the standard. Surface hardness was statistically higher than and comparable to zinc phosphate cement. There was no evidence of potentially clinically significant and deleterious expansion behavior by this cement. All cements tested demonstrated acceptable strength properties. Within the limits of this study, Ceramir C and B is deemed to possess physical properties suitable for a dental luting cement.

[Again review of research design and statistical methods of Chinese Journal of Cardiology].

PubMed

Kong, Qun-yu; Yu, Jin-ming; Jia, Gong-xian; Lin, Fan-li

2012-11-01

To re-evaluate and compare the research design and the use of statistical methods in Chinese Journal of Cardiology. Summary the research design and statistical methods in all of the original papers in Chinese Journal of Cardiology all over the year of 2011, and compared the result with the evaluation of 2008. (1) There is no difference in the distribution of the design of researches of between the two volumes. Compared with the early volume, the use of survival regression and non-parameter test are increased, while decreased in the proportion of articles with no statistical analysis. (2) The proportions of articles in the later volume are significant lower than the former, such as 6(4%) with flaws in designs, 5(3%) with flaws in the expressions, 9(5%) with the incomplete of analysis. (3) The rate of correction of variance analysis has been increased, so as the multi-group comparisons and the test of normality. The error rate of usage has been decreased form 17% to 25% without significance in statistics due to the ignorance of the test of homogeneity of variance. Many improvements showed in Chinese Journal of Cardiology such as the regulation of the design and statistics. The homogeneity of variance should be paid more attention in the further application.

Ocular manifestations of Type 1 diabetes mellitus in pediatric population.

PubMed

Akil, Handan; Buluş, Ayse Derya; Andiran, Nesibe; Alp, Mehmet Numan

2016-09-01

To evaluate the necessity of ocular screening in Type 1 diabetes mellitus (DM). This study aims to investigate the diabetes-related ocular changes according to the glycosylated hemoglobin (HbA1c) level and duration of diabetes in children and compare the results with nondiabetic healthy children. Observational cross-sectional study designed by ophthalmology and pediatric endocrinology clinics. Forty-two children with Type 1 DM, 42 healthy gender- and age-matched children as controls were enrolled. All patients underwent ophthalmic and physical examination, with a review of medical history and current medication. HbA1c level, best corrected visual acuity, intraocular pressure (IOP), central corneal thickness (CCT), tear break-up time (BUT), Schirmer test, dilated fundus examination findings, central retinal thickness (CRT), and total macular volume (TMV) measurements were noted. Descriptive statistics, Student's t-test, Mann-Whitney U-test, Chi-square test for comparison of the group parameters and correlation analyses (Spearman analysis) were performed with SPSS statistical software 17.0 (SPSS Inc., Chicago, IL, USA). Type 1 DM group exhibited significantly reduced Schirmer test, increased IOP and decreased retinal thickness relative to the age-matched control group (P < 0.05) but no statistically significant difference was found for the BUT (P = 0.182) and for the CCT (P = 0.495). The correlations between the age, duration, HbA1c and IOP, BUT, Schirmer test, TMV, CRT measurements did not reach statistical significance. More frequent screening may be needed for complications, including neuropathy-related dry eye syndrome, IOP changes, and diabetic retinopathy in children with Type 1 DM.

On use of the multistage dose-response model for assessing laboratory animal carcinogenicity

PubMed Central

Nitcheva, Daniella; Piegorsch, Walter W.; West, R. Webster

2007-01-01

We explore how well a statistical multistage model describes dose-response patterns in laboratory animal carcinogenicity experiments from a large database of quantal response data. The data are collected from the U.S. EPA’s publicly available IRIS data warehouse and examined statistically to determine how often higher-order values in the multistage predictor yield significant improvements in explanatory power over lower-order values. Our results suggest that the addition of a second-order parameter to the model only improves the fit about 20% of the time, while adding even higher-order terms apparently does not contribute to the fit at all, at least with the study designs we captured in the IRIS database. Also included is an examination of statistical tests for assessing significance of higher-order terms in a multistage dose-response model. It is noted that bootstrap testing methodology appears to offer greater stability for performing the hypothesis tests than a more-common, but possibly unstable, “Wald” test. PMID:17490794

Towards Accurate Modelling of Galaxy Clustering on Small Scales: Testing the Standard ΛCDM + Halo Model

NASA Astrophysics Data System (ADS)

Sinha, Manodeep; Berlind, Andreas A.; McBride, Cameron K.; Scoccimarro, Roman; Piscionere, Jennifer A.; Wibking, Benjamin D.

2018-04-01

Interpreting the small-scale clustering of galaxies with halo models can elucidate the connection between galaxies and dark matter halos. Unfortunately, the modelling is typically not sufficiently accurate for ruling out models statistically. It is thus difficult to use the information encoded in small scales to test cosmological models or probe subtle features of the galaxy-halo connection. In this paper, we attempt to push halo modelling into the "accurate" regime with a fully numerical mock-based methodology and careful treatment of statistical and systematic errors. With our forward-modelling approach, we can incorporate clustering statistics beyond the traditional two-point statistics. We use this modelling methodology to test the standard ΛCDM + halo model against the clustering of SDSS DR7 galaxies. Specifically, we use the projected correlation function, group multiplicity function and galaxy number density as constraints. We find that while the model fits each statistic separately, it struggles to fit them simultaneously. Adding group statistics leads to a more stringent test of the model and significantly tighter constraints on model parameters. We explore the impact of varying the adopted halo definition and cosmological model and find that changing the cosmology makes a significant difference. The most successful model we tried (Planck cosmology with Mvir halos) matches the clustering of low luminosity galaxies, but exhibits a 2.3σ tension with the clustering of luminous galaxies, thus providing evidence that the "standard" halo model needs to be extended. This work opens the door to adding interesting freedom to the halo model and including additional clustering statistics as constraints.

Econometric Assessment of "One Minute" Paper as a Pedagogic Tool

ERIC Educational Resources Information Center

Das, Amaresh

2010-01-01

This paper makes an econometric testing of one-minute paper used as a tool to manage and assess instruction in my statistics class. One of our findings is that the one minute paper when I have tested it by using an OLS estimate in a controlled Vs experimental design framework is found to statistically significant and effective in enhancing…

Conducting tests for statistically significant differences using forest inventory data

Treesearch

James A. Westfall; Scott A. Pugh; John W. Coulston

2013-01-01

Many forest inventory and monitoring programs are based on a sample of ground plots from which estimates of forest resources are derived. In addition to evaluating metrics such as number of trees or amount of cubic wood volume, it is often desirable to make comparisons between resource attributes. To properly conduct statistical tests for differences, it is imperative...

The researcher and the consultant: from testing to probability statements.

PubMed

Hamra, Ghassan B; Stang, Andreas; Poole, Charles

2015-09-01

In the first instalment of this series, Stang and Poole provided an overview of Fisher significance testing (ST), Neyman-Pearson null hypothesis testing (NHT), and their unfortunate and unintended offspring, null hypothesis significance testing. In addition to elucidating the distinction between the first two and the evolution of the third, the authors alluded to alternative models of statistical inference; namely, Bayesian statistics. Bayesian inference has experienced a revival in recent decades, with many researchers advocating for its use as both a complement and an alternative to NHT and ST. This article will continue in the direction of the first instalment, providing practicing researchers with an introduction to Bayesian inference. Our work will draw on the examples and discussion of the previous dialogue.

Statistic analyses of the color experience according to the age of the observer.

PubMed

Hunjet, Anica; Parac-Osterman, Durdica; Vucaj, Edita

2013-04-01

Psychological experience of color is a real state of the communication between the environment and color, and it will depend on the source of the light, angle of the view, and particular on the observer and his health condition. Hering's theory or a theory of the opponent processes supposes that cones, which are situated in the retina of the eye, are not sensible on the three chromatic domains (areas, fields, zones) (red, green and purple-blue), but they produce a signal based on the principle of the opposed pairs of colors. A reason of this theory depends on the fact that certain disorders of the color eyesight, which include blindness to certain colors, cause blindness to pairs of opponent colors. This paper presents a demonstration of the experience of blue and yellow tone according to the age of the observer. For the testing of the statistically significant differences in the omission in the color experience according to the color of the background we use following statistical tests: Mann-Whitnney U Test, Kruskal-Wallis ANOVA and Median test. It was proven that the differences are statistically significant in the elderly persons (older than 35 years).

[Treatment of patients with neuromuscular disease in a warm climate].

PubMed

Dahl, Arve; Skjeldal, Ola H; Simensen, Andreas; Dalen, Håkon E; Bråthen, Tone; Ahlvin, Petra; Svendsby, Ellen Kathrine; Sveinall, Anne; Fredriksen, Per Morten

2004-07-01

Several patient groups request treatment in a warm climate, in spite of the fact that the effects of such treatment are undocumented. 47 children and 40 adults with neuromuscular diseases were recruited, stratified according to sex, use or non-use of electric wheelchair, primary myopathy or hereditary neuropathy, and randomised into two adult and two children groups. The patients were treated in a rehabilitation centre, either on Lanzarote or in Norway. All patients were monitored with physical tests and questionnaires at the start of the study, at the end of the treatment period, after three months (all groups) and after six months (adults only). No significant differences in effect between the groups were found. In the warm climate, the adult patient group showed a statistically significant improvement regarding pain, quality of life, depression, and results of physical tests at the end of treatment. After three months, the improvement in physical tests was still present. Among adult patients treated in Norway, improvement in physical tests was statistically significant after three months, but not at the end of the treatment period. This study did not show a statistically significant difference between patients with various neuromuscular diseases treated in a warm climate compared to similar patients treated in Norway.

Shear Bond Strengths and Morphological Evaluation of Filled and Unfilled Adhesive Interfaces to Enamel and Dentine

PubMed Central

Mortazavi, Vajihesadat; Fathi, Mohammadhosein; Ataei, Ebrahim; Khodaeian, Niloufar; Askari, Navid

2012-01-01

In this laboratory study shear bond strengths of three filled and one unfilled adhesive systems to enamel and dentine were compared. Forty-eight extracted intact noncarious human mandibular molars were randomly assigned to two groups of 24 one for bonding to enamel and the other for bonding to dentine. Buccal and lingual surfaces of each tooth were randomly assigned for application of each one of filled (Prime & Bond NT (PBNT), Optibond Solo Plus (OBSP), and Clearfil SE Bond (CSEB)) and unfilled (Single Bond (SB)) adhesive systems (n = 12). A universal resin composite was placed into the translucent plastic cylinders (3 mm in diameter and 2 mm in length) and seated against the enamel and dentine surfaces and polymerized for 40 seconds. Shear bond strength was determined using a universal testing machine, and the results were statistically analyzed using two-way ANOVA, one-way ANOVA, t-test, and Tukey HSD post hoc test with a 5% level of significance.There were no statistically significant differences in bond strength between the adhesive systems in enamel, but CSEB and SB exhibited significantly higher and lower bond strength to dentine, respectively, than the other tested adhesive systems while there were no statistically significant differences between PBNT and OBSP. PMID:23209471

A Novel Genome-Information Content-Based Statistic for Genome-Wide Association Analysis Designed for Next-Generation Sequencing Data

PubMed Central

Luo, Li; Zhu, Yun

2012-01-01

Abstract The genome-wide association studies (GWAS) designed for next-generation sequencing data involve testing association of genomic variants, including common, low frequency, and rare variants. The current strategies for association studies are well developed for identifying association of common variants with the common diseases, but may be ill-suited when large amounts of allelic heterogeneity are present in sequence data. Recently, group tests that analyze their collective frequency differences between cases and controls shift the current variant-by-variant analysis paradigm for GWAS of common variants to the collective test of multiple variants in the association analysis of rare variants. However, group tests ignore differences in genetic effects among SNPs at different genomic locations. As an alternative to group tests, we developed a novel genome-information content-based statistics for testing association of the entire allele frequency spectrum of genomic variation with the diseases. To evaluate the performance of the proposed statistics, we use large-scale simulations based on whole genome low coverage pilot data in the 1000 Genomes Project to calculate the type 1 error rates and power of seven alternative statistics: a genome-information content-based statistic, the generalized T2, collapsing method, multivariate and collapsing (CMC) method, individual χ2 test, weighted-sum statistic, and variable threshold statistic. Finally, we apply the seven statistics to published resequencing dataset from ANGPTL3, ANGPTL4, ANGPTL5, and ANGPTL6 genes in the Dallas Heart Study. We report that the genome-information content-based statistic has significantly improved type 1 error rates and higher power than the other six statistics in both simulated and empirical datasets. PMID:22651812

A novel genome-information content-based statistic for genome-wide association analysis designed for next-generation sequencing data.

PubMed

Luo, Li; Zhu, Yun; Xiong, Momiao

2012-06-01

The genome-wide association studies (GWAS) designed for next-generation sequencing data involve testing association of genomic variants, including common, low frequency, and rare variants. The current strategies for association studies are well developed for identifying association of common variants with the common diseases, but may be ill-suited when large amounts of allelic heterogeneity are present in sequence data. Recently, group tests that analyze their collective frequency differences between cases and controls shift the current variant-by-variant analysis paradigm for GWAS of common variants to the collective test of multiple variants in the association analysis of rare variants. However, group tests ignore differences in genetic effects among SNPs at different genomic locations. As an alternative to group tests, we developed a novel genome-information content-based statistics for testing association of the entire allele frequency spectrum of genomic variation with the diseases. To evaluate the performance of the proposed statistics, we use large-scale simulations based on whole genome low coverage pilot data in the 1000 Genomes Project to calculate the type 1 error rates and power of seven alternative statistics: a genome-information content-based statistic, the generalized T(2), collapsing method, multivariate and collapsing (CMC) method, individual χ(2) test, weighted-sum statistic, and variable threshold statistic. Finally, we apply the seven statistics to published resequencing dataset from ANGPTL3, ANGPTL4, ANGPTL5, and ANGPTL6 genes in the Dallas Heart Study. We report that the genome-information content-based statistic has significantly improved type 1 error rates and higher power than the other six statistics in both simulated and empirical datasets.

Subtle Cognitive Effects of Moderate Hypoxia

DTIC Science & Technology

2009-08-01

using SPSS® 13.0 with significance set at an alpha level of .05 for all statistical tests. A repeated measures analysis of variance (ANOVA) was...there was not statistically significant change in reaction time (p=.781), accuracy (p=.152), or throughout (p=.967) with increasing altitude. The...results indicate that healthy individuals aged 19 to 45 years do not experience significant cognitive deficit, as measured by the CogScreen®-HE, when

[Oral health status of women with normal and high-risk pregnancies].

PubMed

Chaloupka, P; Korečko, V; Turek, J; Merglová, V

2014-01-01

The aim of this study was to compare the oral health status of women with normal pregnancies and those with high-risk pregnancies. A total of 142 women in the third trimester of pregnancy were randomly selected for this study. The pregnant women were divided into two groups: a normal pregnancy group (group F, n = 61) and a high-risk pregnancy group (group R, n = 81). The following variables were recorded for each woman: age, general health status, DMF index, CPITN index, PBI index, amounts of Streptococcus mutans in the saliva and dental treatment needs. The data obtained were analysed statistically. The Mann-Whitney test, Kruskal-Wallis test and chi square test were used, and p-values less than 0.05 were considered statistically significant. The two-sided t-test was used to compare the two cohorts. Women with high-risk pregnancies showed increased values in all measured indices and tests, but there were no statistically significant differences between the two groups in the DMF index, CPITN index and amounts of Streptococcus mutans present in the saliva. Statistically significant differences were detected between the two groups for the PBI index and dental treatment needs. In group F, the maximum PBI index value was 2.9 in group F and 3.8 in group R. Significant differences were found also in mean PBI values. Out of the entire study cohort, 94 women (66.2%) required dental treatment, including 52% (n = 32) of the women with normal pregnancies and 77% (n = 62) of the women with high-risk pregnancies. This study found that women with complications during pregnancy had severe gingivitis and needed more frequent dental treatment than women with normal pregnancies.

Statistical Tests of System Linearity Based on the Method of Surrogate Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hunter, N.; Paez, T.; Red-Horse, J.

When dealing with measured data from dynamic systems we often make the tacit assumption that the data are generated by linear dynamics. While some systematic tests for linearity and determinism are available - for example the coherence fimction, the probability density fimction, and the bispectrum - fi,u-ther tests that quanti$ the existence and the degree of nonlinearity are clearly needed. In this paper we demonstrate a statistical test for the nonlinearity exhibited by a dynamic system excited by Gaussian random noise. We perform the usual division of the input and response time series data into blocks as required by themore » Welch method of spectrum estimation and search for significant relationships between a given input fkequency and response at harmonics of the selected input frequency. We argue that systematic tests based on the recently developed statistical method of surrogate data readily detect significant nonlinear relationships. The paper elucidates the method of surrogate data. Typical results are illustrated for a linear single degree-of-freedom system and for a system with polynomial stiffness nonlinearity.« less

Evaluating regional trends in ground-water nitrate concentrations of the Columbia Basin ground water management area, Washington

USGS Publications Warehouse

Frans, Lonna M.; Helsel, Dennis R.

2005-01-01

Trends in nitrate concentrations in water from 474 wells in 17 subregions in the Columbia Basin Ground Water Management Area (GWMA) in three counties in eastern Washington were evaluated using a variety of statistical techniques, including the Friedman test and the Kendall test. The Kendall test was modified from its typical 'seasonal' version into a 'regional' version by using well locations in place of seasons. No statistically significant trends in nitrate concentrations were identified in samples from wells in the GWMA, the three counties, or the 17 subregions from 1998 to 2002 when all data were included in the analysis. For wells in which nitrate concentrations were greater than 10 milligrams per liter (mg/L), however, a significant downward trend of -0.4 mg/L per year was observed between 1998 and 2002 for the GWMA as a whole, as well as for Adams County (-0.35 mg/L per year) and for Franklin County (-0.46 mg/L per year). Trend analysis for a smaller but longer-term 51-well dataset in Franklin County found a statistically significant upward trend in nitrate concentrations of 0.1 mg/L per year between 1986 and 2003. The largest increase of nitrate concentrations occurred between 1986 and 1991. No statistically significant differences were observed in this dataset between 1998 and 2003 indicating that the increase in nitrate concentrations has leveled off.

DEIVA: a web application for interactive visual analysis of differential gene expression profiles.

PubMed

Harshbarger, Jayson; Kratz, Anton; Carninci, Piero

2017-01-07

Differential gene expression (DGE) analysis is a technique to identify statistically significant differences in RNA abundance for genes or arbitrary features between different biological states. The result of a DGE test is typically further analyzed using statistical software, spreadsheets or custom ad hoc algorithms. We identified a need for a web-based system to share DGE statistical test results, and locate and identify genes in DGE statistical test results with a very low barrier of entry. We have developed DEIVA, a free and open source, browser-based single page application (SPA) with a strong emphasis on being user friendly that enables locating and identifying single or multiple genes in an immediate, interactive, and intuitive manner. By design, DEIVA scales with very large numbers of users and datasets. Compared to existing software, DEIVA offers a unique combination of design decisions that enable inspection and analysis of DGE statistical test results with an emphasis on ease of use.

Hypothesis-Testing Demands Trustworthy Data—A Simulation Approach to Inferential Statistics Advocating the Research Program Strategy

PubMed Central

Krefeld-Schwalb, Antonia; Witte, Erich H.; Zenker, Frank

2018-01-01

In psychology as elsewhere, the main statistical inference strategy to establish empirical effects is null-hypothesis significance testing (NHST). The recent failure to replicate allegedly well-established NHST-results, however, implies that such results lack sufficient statistical power, and thus feature unacceptably high error-rates. Using data-simulation to estimate the error-rates of NHST-results, we advocate the research program strategy (RPS) as a superior methodology. RPS integrates Frequentist with Bayesian inference elements, and leads from a preliminary discovery against a (random) H0-hypothesis to a statistical H1-verification. Not only do RPS-results feature significantly lower error-rates than NHST-results, RPS also addresses key-deficits of a “pure” Frequentist and a standard Bayesian approach. In particular, RPS aggregates underpowered results safely. RPS therefore provides a tool to regain the trust the discipline had lost during the ongoing replicability-crisis. PMID:29740363

Hypothesis-Testing Demands Trustworthy Data-A Simulation Approach to Inferential Statistics Advocating the Research Program Strategy.

PubMed

Krefeld-Schwalb, Antonia; Witte, Erich H; Zenker, Frank

2018-01-01

In psychology as elsewhere, the main statistical inference strategy to establish empirical effects is null-hypothesis significance testing (NHST). The recent failure to replicate allegedly well-established NHST-results, however, implies that such results lack sufficient statistical power, and thus feature unacceptably high error-rates. Using data-simulation to estimate the error-rates of NHST-results, we advocate the research program strategy (RPS) as a superior methodology. RPS integrates Frequentist with Bayesian inference elements, and leads from a preliminary discovery against a (random) H 0 -hypothesis to a statistical H 1 -verification. Not only do RPS-results feature significantly lower error-rates than NHST-results, RPS also addresses key-deficits of a "pure" Frequentist and a standard Bayesian approach. In particular, RPS aggregates underpowered results safely. RPS therefore provides a tool to regain the trust the discipline had lost during the ongoing replicability-crisis.

A note on generalized Genome Scan Meta-Analysis statistics

PubMed Central

Koziol, James A; Feng, Anne C

2005-01-01

Background Wise et al. introduced a rank-based statistical technique for meta-analysis of genome scans, the Genome Scan Meta-Analysis (GSMA) method. Levinson et al. recently described two generalizations of the GSMA statistic: (i) a weighted version of the GSMA statistic, so that different studies could be ascribed different weights for analysis; and (ii) an order statistic approach, reflecting the fact that a GSMA statistic can be computed for each chromosomal region or bin width across the various genome scan studies. Results We provide an Edgeworth approximation to the null distribution of the weighted GSMA statistic, and, we examine the limiting distribution of the GSMA statistics under the order statistic formulation, and quantify the relevance of the pairwise correlations of the GSMA statistics across different bins on this limiting distribution. We also remark on aggregate criteria and multiple testing for determining significance of GSMA results. Conclusion Theoretical considerations detailed herein can lead to clarification and simplification of testing criteria for generalizations of the GSMA statistic. PMID:15717930

Relationship between self-reported upper limb disability and quantitative tests in hand-arm vibration syndrome.

PubMed

Poole, Kerry; Mason, Howard

2007-03-15

To establish the relationship between quantitative tests of hand function and upper limb disability, as measured by the Disability of the Arm, Shoulder and Hand (DASH) questionnaire, in hand-arm vibration syndrome (HAVS). A total of 228 individuals with HAVS were included in this study. Each had undergone a full HAVS assessment by an experienced physician, including quantitative tests of vibrotactile and thermal perception thresholds, maximal hand-grip strength (HG) and the Purdue pegboard (PP) test. Individuals were also asked to complete a DASH questionnaire. PP and HG of the quantitative tests gave the best and statistically significant individual correlations with the DASH disability score (r2 = 0.168 and 0.096). Stepwise linear regression analysis revealed that only PP and HG measurements were statistically significant predictors of upper limb disability (r2 = 0.178). Overall a combination of the PP and HG measurements, rather than each alone, gave slightly better discrimination, although not statistically significant, between normal and abnormal DASH scores with a sensitivity of 73.1% and specificity of 64.3%. Measurements of manual dexterity and hand-grip strength using PP and HG may be useful in helping to confirm lack of upper limb function and 'perceived' disability in HAVS.

Statistical analysis of long-term monitoring data for persistent organic pollutants in the atmosphere at 20 monitoring stations broadly indicates declining concentrations.

PubMed

Kong, Deguo; MacLeod, Matthew; Hung, Hayley; Cousins, Ian T

2014-11-04

During recent decades concentrations of persistent organic pollutants (POPs) in the atmosphere have been monitored at multiple stations worldwide. We used three statistical methods to analyze a total of 748 time series of selected POPs in the atmosphere to determine if there are statistically significant reductions in levels of POPs that have had control actions enacted to restrict or eliminate manufacture, use and emissions. Significant decreasing trends were identified in 560 (75%) of the 748 time series collected from the Arctic, North America, and Europe, indicating that the atmospheric concentrations of these POPs are generally decreasing, consistent with the overall effectiveness of emission control actions. Statistically significant trends in synthetic time series could be reliably identified with the improved Mann-Kendall (iMK) test and the digital filtration (DF) technique in time series longer than 5 years. The temporal trends of new (or emerging) POPs in the atmosphere are often unclear because time series are too short. A statistical detrending method based on the iMK test was not able to identify abrupt changes in the rates of decline of atmospheric POP concentrations encoded into synthetic time series.

A novel measure and significance testing in data analysis of cell image segmentation.

PubMed

Wu, Jin Chu; Halter, Michael; Kacker, Raghu N; Elliott, John T; Plant, Anne L

2017-03-14

Cell image segmentation (CIS) is an essential part of quantitative imaging of biological cells. Designing a performance measure and conducting significance testing are critical for evaluating and comparing the CIS algorithms for image-based cell assays in cytometry. Many measures and methods have been proposed and implemented to evaluate segmentation methods. However, computing the standard errors (SE) of the measures and their correlation coefficient is not described, and thus the statistical significance of performance differences between CIS algorithms cannot be assessed. We propose the total error rate (TER), a novel performance measure for segmenting all cells in the supervised evaluation. The TER statistically aggregates all misclassification error rates (MER) by taking cell sizes as weights. The MERs are for segmenting each single cell in the population. The TER is fully supported by the pairwise comparisons of MERs using 106 manually segmented ground-truth cells with different sizes and seven CIS algorithms taken from ImageJ. Further, the SE and 95% confidence interval (CI) of TER are computed based on the SE of MER that is calculated using the bootstrap method. An algorithm for computing the correlation coefficient of TERs between two CIS algorithms is also provided. Hence, the 95% CI error bars can be used to classify CIS algorithms. The SEs of TERs and their correlation coefficient can be employed to conduct the hypothesis testing, while the CIs overlap, to determine the statistical significance of the performance differences between CIS algorithms. A novel measure TER of CIS is proposed. The TER's SEs and correlation coefficient are computed. Thereafter, CIS algorithms can be evaluated and compared statistically by conducting the significance testing.

Alcohol, indomethacin, and salbutamol. A comparative trial of their use in preterm labor.

PubMed

Spearing, G

1979-02-01

In a comparative trial, ethanol effectively arrested preterm labor for 48 hours for more in 32% of cases, a beta-adrenergic agent (salbutamol) in 60% of cases (not statistically significant), and a combination of ethanol and indomethacin in 70% of cases (statistically significant, P less than 0.5). Labor was delayed for 14 days or more in 36, 60, and 50%, respectively (not statistically significant). The numbers studied were small, and tests of statistical significance were of doubtful value. Salbutamol was more acceptable to patients and the staff than ethanol. The trial was suspended and eventually abandoned due to reports of prostaglandin synthetase inhibitors causing premature closure of the ductus arteriosus. In this series no problems were encountered with the use of indomethacin.

Constructing three emotion knowledge tests from the invariant measurement approach

PubMed Central

Prieto, Gerardo; Burin, Debora I.

2017-01-01

Background Psychological constructionist models like the Conceptual Act Theory (CAT) postulate that complex states such as emotions are composed of basic psychological ingredients that are more clearly respected by the brain than basic emotions. The objective of this study was the construction and initial validation of Emotion Knowledge measures from the CAT frame by means of an invariant measurement approach, the Rasch Model (RM). Psychological distance theory was used to inform item generation. Methods Three EK tests—emotion vocabulary (EV), close emotional situations (CES) and far emotional situations (FES)—were constructed and tested with the RM in a community sample of 100 females and 100 males (age range: 18–65), both separately and conjointly. Results It was corroborated that data-RM fit was sufficient. Then, the effect of type of test and emotion on Rasch-modelled item difficulty was tested. Significant effects of emotion on EK item difficulty were found, but the only statistically significant difference was that between “happiness” and the remaining emotions; neither type of test, nor interaction effects on EK item difficulty were statistically significant. The testing of gender differences was carried out after corroborating that differential item functioning (DIF) would not be a plausible alternative hypothesis for the results. No statistically significant sex-related differences were found out in EV, CES, FES, or total EK. However, the sign of d indicate that female participants were consistently better than male ones, a result that will be of interest for future meta-analyses. Discussion The three EK tests are ready to be used as components of a higher-level measurement process. PMID:28929013

Memory and Trend of Precipitation in China during 1966-2013

NASA Astrophysics Data System (ADS)

Du, M.; Sun, F.; Liu, W.

2017-12-01

As climate change has had a significant impact on water cycle, the characteristic and variation of precipitation under climate change turned into a hotspot in hydrology. This study aims to analyze the trend and memory (both short-term and long-term) of precipitation in China. To do that, we apply statistical tests (including Mann-Kendall test, Ljung-Box test and Hurst exponent) to annual precipitation (P), frequency of rainy day (λ) and mean daily rainfall in days when precipitation occurs (α) in China (1966-2013). We also use a resampling approach to determine the field significance. From there, we evaluate the spatial distribution and percentages of stations with significant memory or trend. We find that the percentages of significant downtrends for λ and significant uptrends for α are significantly larger than the critical values at 95% field significance level, probably caused by the global warming. From these results, we conclude that extra care is necessary when significant results are obtained using statistical tests. This is because the null hypothesis could be rejected by chance and this situation is more likely to occur if spatial correlation is ignored according to the results of the resampling approach.

Assessing the status of airline safety culture and its relationship to key employee attitudes

NASA Astrophysics Data System (ADS)

Owen, Edward L.

The need to identify the factors that influence the overall safety environment and compliance with safety procedures within airline operations is substantial. This study examines the relationships between job satisfaction, the overall perception of the safety culture, and compliance with safety rules and regulations of airline employees working in flight operations. A survey questionnaire administered via the internet gathered responses which were converted to numerical values for quantitative analysis. The results were grouped to provide indications of overall average levels in each of the three categories, satisfaction, perceptions, and compliance. Correlations between data in the three sets were tested for statistical significance using two-sample t-tests assuming equal variances. Strong statistical significance was found between job satisfaction and compliance with safety rules and between perceptions of the safety environment and safety compliance. The relationship between job satisfaction and safety perceptions did not show strong statistical significance.

Evaluation of conventional, protaper hand and protaper rotary instrumentation system for apical extrusion of debris, irrigants and bacteria- An in vitro randomized trial.

PubMed

Kalra, Pinky; Rao, Arathi; Suman, Ethel; Shenoy, Ramya; Suprabha, Baranya-Shrikrishna

2017-02-01

Endodontic instrumentation carries the risk of over extrusion of debris and bacteria. The technique used and the type of instrumentation influences this risk. The purpose of this study was to evaluate and compare the K-file, ProTaper hand and ProTaper rotary instrumentation systems for the amount of apically extruded debris, irrigant solution and intracanal bacteria. Experimental single blinded randomized type of in vitro study with sample of 30 single rooted teeth. Endodontic access cavities were prepared and the root canals were filled with the suspension of E. faecalis . Myers and Montogomery Model was used to collect apically extruded debris and irrigant. Canals were prepared using K files, Hand protapers and Protaper rotary files. Non Parametric test like Kruskal-Wallis and Mann-Whitney U test were applied to determine the significant differences among the group. Tests revealed statistically significant difference between the amount of debris and number of bacteria extruded by the ProTaper hand and the K-files. No statistically significant difference was observed between the amounts of irrigant extruded by the ProTaper hand and the K-file system. Statistically significant differences were observed between the amounts of bacteria and irrigant extruded by the ProTaper rotary and the Protaper hand. No statistically significant difference was observed between the amounts of debris extruded by the ProTaper hand and the K-file system. Amount of apical extrusion of irrigant solution, bacteria and debris are significantly greater with K File instruments and least with Protaper rotary instruments. Key words: Protaper, rotary, periapical extrusion.

Evaluation of the ecological relevance of mysid toxicity tests using population modeling techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhn-Hines, A.; Munns, W.R. Jr.; Lussier, S.

1995-12-31

A number of acute and chronic bioassay statistics are used to evaluate the toxicity and risks of chemical stressors to the mysid shrimp, Mysidopsis bahia. These include LC{sub 50}S from acute tests, NOECs from 7-day and life-cycle tests, and the US EPA Water Quality Criteria Criterion Continuous Concentrations (CCC). Because these statistics are generated from endpoints which focus upon the responses of individual organisms, their relationships to significant effects at higher levels of ecological organization are unknown. This study was conducted to evaluate the quantitative relationships between toxicity test statistics and a concentration-based statistic derived from exposure-response models describing populationmore » growth rate ({lambda}) to stressor concentration. This statistic, C{sup {sm_bullet}} (concentration where {lambda} = I, zero population growth) describes the concentration above which mysid populations are projected to decline in abundance as determined using population modeling techniques. An analysis of M. bahia responses to 9 metals and 9 organic contaminants indicated the NOEC from life-cycle tests to be the best predictor of C{sup {sm_bullet}}, although the acute LC{sub 50} predicted population-level response surprisingly well. These analyses provide useful information regarding uncertainties of extrapolation among test statistics in assessments of ecological risk.« less

Patient safety: numerical skills and drug calculation abilities of nursing students and registered nurses.

PubMed

McMullan, Miriam; Jones, Ray; Lea, Susan

2010-04-01

This paper is a report of a correlational study of the relations of age, status, experience and drug calculation ability to numerical ability of nursing students and Registered Nurses. Competent numerical and drug calculation skills are essential for nurses as mistakes can put patients' lives at risk. A cross-sectional study was carried out in 2006 in one United Kingdom university. Validated numerical and drug calculation tests were given to 229 second year nursing students and 44 Registered Nurses attending a non-medical prescribing programme. The numeracy test was failed by 55% of students and 45% of Registered Nurses, while 92% of students and 89% of nurses failed the drug calculation test. Independent of status or experience, older participants (> or = 35 years) were statistically significantly more able to perform numerical calculations. There was no statistically significant difference between nursing students and Registered Nurses in their overall drug calculation ability, but nurses were statistically significantly more able than students to perform basic numerical calculations and calculations for solids, oral liquids and injections. Both nursing students and Registered Nurses were statistically significantly more able to perform calculations for solids, liquid oral and injections than calculations for drug percentages, drip and infusion rates. To prevent deskilling, Registered Nurses should continue to practise and refresh all the different types of drug calculations as often as possible with regular (self)-testing of their ability. Time should be set aside in curricula for nursing students to learn how to perform basic numerical and drug calculations. This learning should be reinforced through regular practice and assessment.

Effect of repeated simulated clinical use and sterilization on the cutting efficiency and flexibility of Hyflex CM nickel-titanium rotary files.

PubMed

Seago, Scott T; Bergeron, Brian E; Kirkpatrick, Timothy C; Roberts, Mark D; Roberts, Howard W; Himel, Van T; Sabey, Kent A

2015-05-01

Recent nickel-titanium manufacturing processes have resulted in an alloy that remains in a twinned martensitic phase at operating temperature. This alloy has been shown to have increased flexibility with added tolerance to cyclic and torsional fatigue. The aim of this study was to assess the effect of repeated simulated clinical use and sterilization on cutting efficiency and flexibility of Hyflex CM rotary files. Cutting efficiency was determined by measuring the load required to maintain a constant feed rate while instrumenting simulated canals. Flexibility was determined by using a 3-point bending test. Files were autoclaved after each use according to the manufacturer's recommendations. Files were tested through 10 simulated clinical uses. For cutting efficiency, mean data were analyzed by using multiple factor analysis of variance and the Dunnett post hoc test (P < .05). For flexibility, mean data were analyzed by using Levene's Test of Equality of Error and a general linear model (P < .05). No statistically significant decrease in cutting efficiency was noted in groups 2, 5, 6, and 7. A statistically significant decrease in cutting efficiency was noted in groups 3, 4, 8, 9, and 10. No statistically significant decrease in flexibility was noted in groups 2, 3, and 7. A statistically significant decrease in flexibility was noted in groups 4, 5, 6, 8, 9, 10, and 11. Repeated simulated clinical use and sterilization showed no effect on cutting efficiency through 1 use and no effect on flexibility through 2 uses. Published by Elsevier Inc.

Retention of veneered stainless steel crowns on replicated typodont primary incisors: an in vitro study.

PubMed

Guelmann, Marcio; Gehring, Daren F; Turner, Clara

2003-01-01

The purpose of this in vitro study was to determine the effect of crimping and cementation on retention of veneered stainless steel crowns. One hundred twenty crowns, 90 from 3 commercially available brands of veneered stainless steel crowns (Dura Crown, Kinder Krown, and NuSmile Primary Crown) and 30 (plain) Unitek stainless steel crowns were assessed for retention. An orthodontic wire was soldered perpendicular to the incisal edge of the crowns; the crowns were fitted to acrylic replicas of ideal crown preparations and were divided equally into 3 test groups: group 1--crowns were crimped only (no cement used); group 2--crowns were cemented only; and group 3--crowns were crimped and cemented to the acrylic replicas. An Instron machine recorded the amount of force necessary to dislodge the crowns and the results were statistically analyzed using 2-way ANOVA and Tukey honestly significant difference (HSD) test. Group 3 was statistically more retentive than groups 1 and 2. Group 2 was statistically more retentive than group 1 (P < .001). In group 1, Unitek crowns were statistically more retentive than the veneered crowns (P < .05). In group 2, NuSmile crowns showed statistically less retention values than all other crowns (P < .05). In group 3,Kinder Krown crowns showed statistically better retention rates than all other brands (P < .05). Significantly higher retention values were obtained for all brands tested when crimping and cement were combined. The crowns with veneer facings were significantly more retentive than the nonveneered ones when cement and crimping were combined.

The relationship between the behavior problems and motor skills of students with intellectual disability.

PubMed

Lee, Yangchool; Jeoung, Bogja

2016-12-01

The purpose of this study was to determine the relationship between the motor skills and the behavior problems of students with intellectual disabilities. The study participants were 117 students with intellectual disabilities who were between 7 and 25 years old (male, n=79; female, n=38) and attending special education schools in South Korea. Motor skill abilities were assessed by using the second version of the Bruininks-Oseretsky test of motor proficiency, which includes subtests in fine motor control, manual coordination, body coordination, strength, and agility. Data were analyzed with SPSS IBM 21 by using correlation and regression analyses, and the significance level was set at P <0.05. The results showed that fine motor precision and integration had a statistically significant influence on aggressive behavior. Manual dexterity showed a statistically significant influence on somatic complaint and anxiety/depression, and bilateral coordination had a statistically significant influence on social problems, attention problem, and aggressive behavior. Our results showed that balance had a statistically significant influence on social problems and aggressive behavior, and speed and agility had a statistically significant influence on social problems and aggressive behavior. Upper limb coordination and strength had a statistically significant influence on social problems.

Statistical test for ΔρDCCA cross-correlation coefficient

NASA Astrophysics Data System (ADS)

Guedes, E. F.; Brito, A. A.; Oliveira Filho, F. M.; Fernandez, B. F.; de Castro, A. P. N.; da Silva Filho, A. M.; Zebende, G. F.

2018-07-01

In this paper we propose a new statistical test for ΔρDCCA, Detrended Cross-Correlation Coefficient Difference, a tool to measure contagion/interdependence effect in time series of size N at different time scale n. For this proposition we analyzed simulated and real time series. The results showed that the statistical significance of ΔρDCCA depends on the size N and the time scale n, and we can define a critical value for this dependency in 90%, 95%, and 99% of confidence level, as will be shown in this paper.

On two-sample McNemar test.

PubMed

Xiang, Jim X

2016-01-01

Measuring a change in the existence of disease symptoms before and after a treatment is examined for statistical significance by means of the McNemar test. When comparing two treatments, Feuer and Kessler (1989) proposed a two-sample McNemar test. In this article, we show that this test usually inflates the type I error in the hypothesis testing, and propose a new two-sample McNemar test that is superior in terms of preserving type I error. We also make the connection between the two-sample McNemar test and the test statistic for the equal residual effects in a 2 × 2 crossover design. The limitations of the two-sample McNemar test are also discussed.

Effect of Kınesıotapıng and Knee Brace on Functıonal Performance in Recreatıonal Athletes

PubMed Central

Ulusoy, Burak; İldiz, Bülent; Tunay, Volga Bayrakçı

2014-01-01

Objectives: Kinesiotaping is a popular taping method that is used for both therapeutic and performance enchancement purposes. Knee braces are widely used for prevention in sport injuries but their performance effectiveness is still controversial. The aim of this study was to determine whether kinesiotape or brace was more effective on functional performance. Methods: A total twenty male recreational football players (Mean±Standart Deviation (SD) age: 22.5±0.68 years, height: 175.15±3.37 cm, body weight: 74.52±12.41 kg), voluntarily participated in this study. Participants were tested with kinesiotape, with brace and without kinesiotape and brace. Tests were applied one day after patellar kinesiotaping (correction technique). Balance property measured with Modified Y balance Test (dynamic test), agility measured by T test, muscle strength and anaerobic power assessed by vertical jump and triple hop tests. Wilcoxon signed rank test was employed for determining the statistical significance of tests with kinesiotape, with brace and without kinesiotape and brace. Results: In analysis; There were statistically significant differences found in Triple hop test with kinesiotaping and without kinesiotaping and brace, in T test with bracing and kinesiotaping, in vertical jump with kinesiotaping and without kinesiotaping and brace (p<0.001) (in the favour of kinesiotaping in all tests) No statistically significant difference was found in modified Y balance test all groups (p> 0.05). Conclusion: Consequently, kinesiotaping had positive effects on agility and muscle strength but had no effects on balance in football players. On the other hand, brace had no effects on functional performance tests.

Statistical tests to compare motif count exceptionalities

PubMed Central

Robin, Stéphane; Schbath, Sophie; Vandewalle, Vincent

2007-01-01

Background Finding over- or under-represented motifs in biological sequences is now a common task in genomics. Thanks to p-value calculation for motif counts, exceptional motifs are identified and represent candidate functional motifs. The present work addresses the related question of comparing the exceptionality of one motif in two different sequences. Just comparing the motif count p-values in each sequence is indeed not sufficient to decide if this motif is significantly more exceptional in one sequence compared to the other one. A statistical test is required. Results We develop and analyze two statistical tests, an exact binomial one and an asymptotic likelihood ratio test, to decide whether the exceptionality of a given motif is equivalent or significantly different in two sequences of interest. For that purpose, motif occurrences are modeled by Poisson processes, with a special care for overlapping motifs. Both tests can take the sequence compositions into account. As an illustration, we compare the octamer exceptionalities in the Escherichia coli K-12 backbone versus variable strain-specific loops. Conclusion The exact binomial test is particularly adapted for small counts. For large counts, we advise to use the likelihood ratio test which is asymptotic but strongly correlated with the exact binomial test and very simple to use. PMID:17346349

Genotoxicity of AMPA, the environmental metabolite of glyphosate, assessed by the Comet assay and cytogenetic tests.

PubMed

Mañas, F; Peralta, L; Raviolo, J; García Ovando, H; Weyers, A; Ugnia, L; Gonzalez Cid, M; Larripa, I; Gorla, N

2009-03-01

Formulations containing glyphosate are the most widely used herbicides in the world. AMPA is the major environmental breakdown product of glyphosate. The purpose of this study is to evaluate the in vitro genotoxicity of AMPA using the Comet assay in Hep-2 cells after 4h of incubation and the chromosome aberration (CA) test in human lymphocytes after 48h of exposition. Potential in vivo genotoxicity was evaluated through the micronucleus test in mice. In the Comet assay, the level of DNA damage in exposed cells at 2.5-7.5mM showed a significant increase compared with the control group. In human lymphocytes we found statistically significant clastogenic effect AMPA at 1.8mM compared with the control group. In vivo, the micronucleus test rendered significant statistical increases at 200-400mg/kg. AMPA was genotoxic in the three performed tests. Very scarce data are available about AMPA potential genotoxicity.

Statistical aspects of genetic association testing in small samples, based on selective DNA pooling data in the arctic fox.

PubMed

Szyda, Joanna; Liu, Zengting; Zatoń-Dobrowolska, Magdalena; Wierzbicki, Heliodor; Rzasa, Anna

2008-01-01

We analysed data from a selective DNA pooling experiment with 130 individuals of the arctic fox (Alopex lagopus), which originated from 2 different types regarding body size. The association between alleles of 6 selected unlinked molecular markers and body size was tested by using univariate and multinomial logistic regression models, applying odds ratio and test statistics from the power divergence family. Due to the small sample size and the resulting sparseness of the data table, in hypothesis testing we could not rely on the asymptotic distributions of the tests. Instead, we tried to account for data sparseness by (i) modifying confidence intervals of odds ratio; (ii) using a normal approximation of the asymptotic distribution of the power divergence tests with different approaches for calculating moments of the statistics; and (iii) assessing P values empirically, based on bootstrap samples. As a result, a significant association was observed for 3 markers. Furthermore, we used simulations to assess the validity of the normal approximation of the asymptotic distribution of the test statistics under the conditions of small and sparse samples.

A SIGNIFICANCE TEST FOR THE LASSO1

PubMed Central

Lockhart, Richard; Taylor, Jonathan; Tibshirani, Ryan J.; Tibshirani, Robert

2014-01-01

In the sparse linear regression setting, we consider testing the significance of the predictor variable that enters the current lasso model, in the sequence of models visited along the lasso solution path. We propose a simple test statistic based on lasso fitted values, called the covariance test statistic, and show that when the true model is linear, this statistic has an Exp(1) asymptotic distribution under the null hypothesis (the null being that all truly active variables are contained in the current lasso model). Our proof of this result for the special case of the first predictor to enter the model (i.e., testing for a single significant predictor variable against the global null) requires only weak assumptions on the predictor matrix X. On the other hand, our proof for a general step in the lasso path places further technical assumptions on X and the generative model, but still allows for the important high-dimensional case p > n, and does not necessarily require that the current lasso model achieves perfect recovery of the truly active variables. Of course, for testing the significance of an additional variable between two nested linear models, one typically uses the chi-squared test, comparing the drop in residual sum of squares (RSS) to a χ12 distribution. But when this additional variable is not fixed, and has been chosen adaptively or greedily, this test is no longer appropriate: adaptivity makes the drop in RSS stochastically much larger than χ12 under the null hypothesis. Our analysis explicitly accounts for adaptivity, as it must, since the lasso builds an adaptive sequence of linear models as the tuning parameter λ decreases. In this analysis, shrinkage plays a key role: though additional variables are chosen adaptively, the coefficients of lasso active variables are shrunken due to the l1 penalty. Therefore, the test statistic (which is based on lasso fitted values) is in a sense balanced by these two opposing properties—adaptivity and shrinkage—and its null distribution is tractable and asymptotically Exp(1). PMID:25574062

40 CFR Appendix IV to Part 265 - Tests for Significance

Code of Federal Regulations, 2014 CFR

2014-07-01

... changes in the concentration or value of an indicator parameter in periodic ground-water samples when... then be compared to the value of the t-statistic found in a table for t-test of significance at the specified level of significance. A calculated value of t which exceeds the value of t found in the table...

40 CFR Appendix IV to Part 265 - Tests for Significance

Code of Federal Regulations, 2011 CFR

2011-07-01

... changes in the concentration or value of an indicator parameter in periodic ground-water samples when... then be compared to the value of the t-statistic found in a table for t-test of significance at the specified level of significance. A calculated value of t which exceeds the value of t found in the table...

40 CFR Appendix IV to Part 265 - Tests for Significance

Code of Federal Regulations, 2012 CFR

2012-07-01

... changes in the concentration or value of an indicator parameter in periodic ground-water samples when... then be compared to the value of the t-statistic found in a table for t-test of significance at the specified level of significance. A calculated value of t which exceeds the value of t found in the table...

40 CFR Appendix IV to Part 265 - Tests for Significance

Code of Federal Regulations, 2013 CFR

2013-07-01

... changes in the concentration or value of an indicator parameter in periodic ground-water samples when... then be compared to the value of the t-statistic found in a table for t-test of significance at the specified level of significance. A calculated value of t which exceeds the value of t found in the table...

[Statistical approach to evaluate the occurrence of out-of acceptable ranges and accuracy for antimicrobial susceptibility tests in inter-laboratory quality control program].

PubMed

Ueno, Tamio; Matuda, Junichi; Yamane, Nobuhisa

2013-03-01

To evaluate the occurrence of out-of acceptable ranges and accuracy of antimicrobial susceptibility tests, we applied a new statistical tool to the Inter-Laboratory Quality Control Program established by the Kyushu Quality Control Research Group. First, we defined acceptable ranges of minimum inhibitory concentration (MIC) for broth microdilution tests and inhibitory zone diameter for disk diffusion tests on the basis of Clinical and Laboratory Standards Institute (CLSI) M100-S21. In the analysis, more than two out-of acceptable range results in the 20 tests were considered as not allowable according to the CLSI document. Of the 90 participating laboratories, 46 (51%) experienced one or more occurrences of out-of acceptable range results. Then, a binomial test was applied to each participating laboratory. The results indicated that the occurrences of out-of acceptable range results in the 11 laboratories were significantly higher when compared to the CLSI recommendation (allowable rate < or = 0.05). The standard deviation indices(SDI) were calculated by using reported results, mean and standard deviation values for the respective antimicrobial agents tested. In the evaluation of accuracy, mean value from each laboratory was statistically compared with zero using a Student's t-test. The results revealed that 5 of the 11 above laboratories reported erroneous test results that systematically drifted to the side of resistance. In conclusion, our statistical approach has enabled us to detect significantly higher occurrences and source of interpretive errors in antimicrobial susceptibility tests; therefore, this approach can provide us with additional information that can improve the accuracy of the test results in clinical microbiology laboratories.

Evaluation of bond strength of various epoxy resin based sealers in oval shaped root canals.

PubMed

Cakici, Fatih; Cakici, Elif Bahar; Ceyhanli, Kadir Tolga; Celik, Ersan; Kucukekenci, Funda Fundaoglu; Gunseren, Arif Onur

2016-09-30

The aim of this study was to evaluate the bond strength of AH plus, Acroseal, and Adseal to the root canal dentin. A total of 36 single-rooted, mandibular premolar teeth were used. Root canal shaping procedures were performed with ProTaper rotary instruments (Dentsply Maillefer) up to size F4. The prepared samples were then randomly assembled into 3 groups (n = 12). For each group, an ultrasonic tip (size 15, 0.02 taper) which was also coated with an epoxy resin based sealer and placed 2 mm shorter than the working length. The sealer was then activated for 10 s. A push-out test was used to measure the bond strength between the root canal dentine and the sealer. Kruskal-Wallis test to evaluate the push-out bond strength of epoxy based sealer (P = 0.05). The failure mode data were statistically analyzed using Pearson's chi square test (P = 0.05). Kruskal-Wallis test indicated that there were no statistically significant difference among the push out bond strength values of 3 mm (p = 0.123) and 6 mm (P = 0.057) for groups, there was statistically significant difference push out bond strength value of 9 mm (P = 0.032). Pearson's chi square test showed statistically significant differences for the failure types among the groups. Various epoxy resin based sealers activated ultrasonically showed similar bond strength in oval shaped root canals. Apical sections for all groups have higher push out bond strength values than middle and coronal sections.

Comparative Evaluation of Microleakage Between Nano-Ionomer, Giomer and Resin Modified Glass Ionomer Cement in Class V Cavities- CLSM Study

PubMed Central

Hari, Archana; Thumu, Jayaprakash; Velagula, Lakshmi Deepa; Bolla, Nagesh; Varri, Sujana; Kasaraneni, Srikanth; Nalli, Siva Venkata Malathi

2016-01-01

Introduction Marginal integrity of adhesive restorative materials provides better sealing ability for enamel and dentin and plays an important role in success of restoration in Class V cavities. Restorative material with good marginal adaptation improves the longevity of restorations. Aim Aim of this study was to evaluate microleakage in Class V cavities which were restored with Resin Modified Glass Ionomer Cement (RMGIC), Giomer and Nano-Ionomer. Materials and Methods This in-vitro study was performed on 60 human maxillary and mandibular premolars which were extracted for orthodontic reasons. A standard wedge shaped defect was prepared on the buccal surfaces of teeth with the gingival margin placed near Cemento Enamel Junction (CEJ). Teeth were divided into three groups of 20 each and restored with RMGIC, Giomer and Nano-Ionomer and were subjected to thermocycling. Teeth were then immersed in 0.5% Rhodamine B dye for 48 hours. They were sectioned longitudinally from the middle of cavity into mesial and distal parts. The sections were observed under Confocal Laser Scanning Microscope (CLSM) to evaluate microleakage. Depth of dye penetration was measured in millimeters. Statistical Analysis The data was analysed using the Kruskal Wallis test. Pair wise comparison was done with Mann Whitney U Test. A p-value<0.05 is taken as statistically significant. Results Nano-Ionomer showed less microleakage which was statistically significant when compared to Giomer (p=0.0050). Statistically no significant difference was found between Nano Ionomer and RMGIC (p=0.3550). There was statistically significant difference between RMGIC and Giomer (p=0.0450). Conclusion Nano-Ionomer and RMGIC showed significantly less leakage and better adaptation than Giomer and there was no statistically significant difference between Nano-Ionomer and RMGIC. PMID:27437363

The effects of hands-on-science instruction on the science achievement of middle school students

NASA Astrophysics Data System (ADS)

Wiggins, Felita

Student achievement in the Twenty First Century demands a new rigor in student science knowledge, since advances in science and technology require students to think and act like scientists. As a result, students must acquire proficient levels of knowledge and skills to support a knowledge base that is expanding exponentially with new scientific advances. This study examined the effects of hands-on-science instruction on the science achievement of middle school students. More specifically, this study was concerned with the influence of hands-on science instruction versus traditional science instruction on the science test scores of middle school students. The subjects in this study were one hundred and twenty sixth-grade students in six classes. Instruction involved lecture/discussion and hands-on activities carried out for a three week period. Specifically, the study ascertained the influence of the variables gender, ethnicity, and socioeconomic status on the science test scores of middle school students. Additionally, this study assessed the effect of the variables gender, ethnicity, and socioeconomic status on the attitudes of sixth grade students toward science. The two instruments used to collect data for this study were the Prentice Hall unit ecosystem test and the Scientific Work Experience Programs for Teachers Study (SWEPT) student's attitude survey. Moreover, the data for the study was treated using the One-Way Analysis of Covariance and the One-Way Analysis of Variance. The following findings were made based on the results: (1) A statistically significant difference existed in the science performance of middle school students exposed to hands-on science instruction. These students had significantly higher scores than the science performance of middle school students exposed to traditional instruction. (2) A statistically significant difference did not exist between the science scores of male and female middle school students. (3) A statistically significant difference did not exist between the science scores of African American and non-African American middle school students. (4) A statistically significant difference existed in the socioeconomic status of students who were not provided with assisted lunches. Students with unassisted lunches had significantly higher science scores than those middle school students who were provided with assisted lunches. (5) A statistically significant difference was not found in the attitude scores of middle school students who were exposed to hands-on or traditional science instruction. (6) A statistically significant difference was not found in the observed attitude scores of middle school students who were exposed to either hands-on or traditional science instruction by their socioeconomic status. (7) A statistically significant difference was not found in the observed attitude scores of male and female students. (8) A statistically significant difference was not found in the observed attitude scores of African American and non African American students.

The other half of the story: effect size analysis in quantitative research.

PubMed

Maher, Jessica Middlemis; Markey, Jonathan C; Ebert-May, Diane

2013-01-01

Statistical significance testing is the cornerstone of quantitative research, but studies that fail to report measures of effect size are potentially missing a robust part of the analysis. We provide a rationale for why effect size measures should be included in quantitative discipline-based education research. Examples from both biological and educational research demonstrate the utility of effect size for evaluating practical significance. We also provide details about some effect size indices that are paired with common statistical significance tests used in educational research and offer general suggestions for interpreting effect size measures. Finally, we discuss some inherent limitations of effect size measures and provide further recommendations about reporting confidence intervals.

Towards accurate modelling of galaxy clustering on small scales: testing the standard ΛCDM + halo model

NASA Astrophysics Data System (ADS)

Sinha, Manodeep; Berlind, Andreas A.; McBride, Cameron K.; Scoccimarro, Roman; Piscionere, Jennifer A.; Wibking, Benjamin D.

2018-07-01

Interpreting the small-scale clustering of galaxies with halo models can elucidate the connection between galaxies and dark matter haloes. Unfortunately, the modelling is typically not sufficiently accurate for ruling out models statistically. It is thus difficult to use the information encoded in small scales to test cosmological models or probe subtle features of the galaxy-halo connection. In this paper, we attempt to push halo modelling into the `accurate' regime with a fully numerical mock-based methodology and careful treatment of statistical and systematic errors. With our forward-modelling approach, we can incorporate clustering statistics beyond the traditional two-point statistics. We use this modelling methodology to test the standard Λ cold dark matter (ΛCDM) + halo model against the clustering of Sloan Digital Sky Survey (SDSS) seventh data release (DR7) galaxies. Specifically, we use the projected correlation function, group multiplicity function, and galaxy number density as constraints. We find that while the model fits each statistic separately, it struggles to fit them simultaneously. Adding group statistics leads to a more stringent test of the model and significantly tighter constraints on model parameters. We explore the impact of varying the adopted halo definition and cosmological model and find that changing the cosmology makes a significant difference. The most successful model we tried (Planck cosmology with Mvir haloes) matches the clustering of low-luminosity galaxies, but exhibits a 2.3σ tension with the clustering of luminous galaxies, thus providing evidence that the `standard' halo model needs to be extended. This work opens the door to adding interesting freedom to the halo model and including additional clustering statistics as constraints.

Statistical inference methods for sparse biological time series data.

PubMed

Ndukum, Juliet; Fonseca, Luís L; Santos, Helena; Voit, Eberhard O; Datta, Susmita

2011-04-25

Comparing metabolic profiles under different biological perturbations has become a powerful approach to investigating the functioning of cells. The profiles can be taken as single snapshots of a system, but more information is gained if they are measured longitudinally over time. The results are short time series consisting of relatively sparse data that cannot be analyzed effectively with standard time series techniques, such as autocorrelation and frequency domain methods. In this work, we study longitudinal time series profiles of glucose consumption in the yeast Saccharomyces cerevisiae under different temperatures and preconditioning regimens, which we obtained with methods of in vivo nuclear magnetic resonance (NMR) spectroscopy. For the statistical analysis we first fit several nonlinear mixed effect regression models to the longitudinal profiles and then used an ANOVA likelihood ratio method in order to test for significant differences between the profiles. The proposed methods are capable of distinguishing metabolic time trends resulting from different treatments and associate significance levels to these differences. Among several nonlinear mixed-effects regression models tested, a three-parameter logistic function represents the data with highest accuracy. ANOVA and likelihood ratio tests suggest that there are significant differences between the glucose consumption rate profiles for cells that had been--or had not been--preconditioned by heat during growth. Furthermore, pair-wise t-tests reveal significant differences in the longitudinal profiles for glucose consumption rates between optimal conditions and heat stress, optimal and recovery conditions, and heat stress and recovery conditions (p-values <0.0001). We have developed a nonlinear mixed effects model that is appropriate for the analysis of sparse metabolic and physiological time profiles. The model permits sound statistical inference procedures, based on ANOVA likelihood ratio tests, for testing the significance of differences between short time course data under different biological perturbations.

Steadiness of Spinal Regions during Single-Leg Standing in Older Adults with and without Chronic Low Back Pain

PubMed Central

Kuo, Yi-Liang; Huang, Kuo-Yuan; Chiang, Pei-Tzu; Lee, Pei-Yun; Tsai, Yi-Ju

2015-01-01

The aims of this study were to compare the steadiness index of spinal regions during single-leg standing in older adults with and without chronic low back pain (LBP) and to correlate measurements of steadiness index with the performance of clinical balance tests. Thirteen community-dwelling older adults (aged 55 years or above) with chronic LBP and 13 age- and gender-matched asymptomatic volunteers participated in this study. Data collection was conducted in a university research laboratory. Measurements were steadiness index of spinal regions (trunk, thoracic spine, lumbar spine, and pelvis) during single-leg standing including relative holding time (RHT) and relative standstill time (RST), and clinical balance tests (timed up and go test and 5-repetition sit to stand test). The LBP group had a statistically significantly smaller RHT than the control group, regardless of one leg stance on the painful or non-painful sides. The RSTs on the painful side leg in the LBP group were not statistically significantly different from the average RSTs of both legs in the control group; however, the RSTs on the non-painful side leg in the LBP group were statistically significantly smaller than those in the control group for the trunk, thoracic spine, and lumbar spine. No statistically significant intra-group differences were found in the RHTs and RSTs between the painful and non-painful side legs in the LBP group. Measurements of clinical balance tests also showed insignificant weak to moderate correlations with steadiness index. In conclusion, older adults with chronic LBP demonstrated decreased spinal steadiness not only in the symptomatic lumbar spine but also in the other spinal regions within the kinetic chain of the spine. When treating older adults with chronic LBP, clinicians may also need to examine their balance performance and spinal steadiness during balance challenging tests. PMID:26024534

The Relative Importance of Low Significance Level and High Power in Multiple Tests of Significance.

ERIC Educational Resources Information Center

Westermann, Rainer; Hager, Willi

1983-01-01

Two psychological experiments--Anderson and Shanteau (1970), Berkowitz and LePage (1967)--are reanalyzed to present the problem of the relative importance of low Type 1 error probability and high power when answering a research question by testing several statistical hypotheses. (Author/PN)

The Effect of a Read Aloud Accommodation on Test Scores of Students with and without a Learning Disability in Reading.

ERIC Educational Resources Information Center

Meloy, Linda L.; Deville, Craig; Frisbie, David A.

2002-01-01

A study examined the effect of a read aloud testing accommodation on 260 middle school students with and without learning disabilities in reading. Students with learning disabilities in reading, as well as those without, exhibited statistically significant gains with the read aloud test administration. Interaction effects were not significant.…

A comparison of face to face and group education on informed choice and decisional conflict of pregnant women about screening tests of fetal abnormalities.

PubMed

Kordi, Masoumeh; Riyazi, Sahar; Lotfalizade, Marziyeh; Shakeri, Mohammad Taghi; Suny, Hoseyn Jafari

2018-01-01

Screening of fetal anomalies is assumed as a necessary measurement in antenatal cares. The screening plans aim at empowerment of individuals to make the informed choice. This study was conducted in order to compare the effect of group and face-to-face education and decisional conflicts among the pregnant females regarding screening of fetal abnormalities. This study of the clinical trial was carried out on 240 pregnant women at <10-week pregnancy age in health care medical centers in Mashhad city in 2014. The form of individual-midwifery information and informed choice questionnaire and decisional conflict scale were used as tools for data collection. The face-to-face and group education course were held in two weekly sessions for intervention groups during two consecutive weeks, and the usual care was conducted for the control group. The rate of informed choice and decisional conflict was measured in pregnant women before education and also at weeks 20-22 of pregnancy in three groups. The data analysis was executed using SPSS statistical software (version 16), and statistical tests were implemented including Chi-square test, Kruskal-Wallis test, Wilcoxon test, Mann-Whitney U-test, one-way analysis of variance test, and Tukey's range test. The P < 0.05 was considered as a significant. The results showed that there was statically significant difference between three groups in terms of frequency of informed choice in screening of fetal abnormalities ( P = 0.001) in such a way that at next step of intervention, 62 participants (77.5%) in face-to-face education group, 64 members (80%) in group education class, and 20 persons (25%) in control group had the informed choice regarding screening tests, but there was no statistically significant difference between two individual and group education classes. Similarly, during the postintervention phase, there was a statistically significant difference in mean score of decisional conflict scale among pregnant women regarding screening tests in three groups ( P = 0.001). With respect to effectiveness of group and face-to-face education methods in increasing the informed choice and reduced decisional conflict in pregnant women regarding screening tests, each of these education methods may be employed according to the clinical environment conditions and requirement to encourage the women for conducting the screening tests.

Shear bond strength of orthodontic color-change adhesives with different light-curing times

PubMed Central

Bayani, Shahin; Ghassemi, Amirreza; Manafi, Safa; Delavarian, Mohadeseh

2015-01-01

Background: The purpose of this study was to evaluate the effect of light-curing time on the shear bond strength (SBS) of two orthodontic color-change adhesives (CCAs). Materials and Methods: A total of 72 extracted premolars were randomly assigned into 6 groups of 12 teeth each. Subsequent to primer application, a metal bracket was bonded to the buccal surface using an orthodontic adhesive. Two CCAs (Greengloo and Transbond Plus) were tested and one conventional light-cured adhesive (Resilience) served as control. For each adhesive, the specimens were light-cured for two different times of 20 and 40 s. All the specimens underwent mechanical testing using a universal testing machine to measure the SBS. Adhesive remnant index (ARI) was used to assess the remnant adhesive material on the tooth surface. All statistical analyses were performed using SPSS software. The significance level for all statistical tests was set at P ≤ 0.05. Results: The SBSs of the tested groups were in the range of 14.05-31.25 MPa. Greengloo adhesive showed the highest SBS values when light-cured for 40 s, and Transbond Plus adhesive showed the lowest values when light-cured for 20 s. ARI scores of Transbond Plus adhesive were significantly higher than those of controls, while other differences in ARI values were not significant. Conclusion: Within the limitations of his study, decreasing the light-curing time from 40 to 20 s decreased the SBS of the tested adhesives; however, this decline in SBS was statistically significant only in Transbond Plus adhesive PMID:26005468

Potential Mediators in Parenting and Family Intervention: Quality of Mediation Analyses

PubMed Central

Patel, Chandni C.; Fairchild, Amanda J.; Prinz, Ronald J.

2017-01-01

Parenting and family interventions have repeatedly shown effectiveness in preventing and treating a range of youth outcomes. Accordingly, investigators in this area have conducted a number of studies using statistical mediation to examine some of the potential mechanisms of action by which these interventions work. This review examined from a methodological perspective in what ways and how well the family-based intervention studies tested statistical mediation. A systematic search identified 73 published outcome studies that tested mediation for family-based interventions across a wide range of child and adolescent outcomes (i.e., externalizing, internalizing, and substance-abuse problems; high-risk sexual activity; and academic achievement), for putative mediators pertaining to positive and negative parenting, family functioning, youth beliefs and coping skills, and peer relationships. Taken as a whole, the studies used designs that adequately addressed temporal precedence. The majority of studies used the product of coefficients approach to mediation, which is preferred, and less limiting than the causal steps approach. Statistical significance testing did not always make use of the most recently developed approaches, which would better accommodate small sample sizes and more complex functions. Specific recommendations are offered for future mediation studies in this area with respect to full longitudinal design, mediation approach, significance testing method, documentation and reporting of statistics, testing of multiple mediators, and control for Type I error. PMID:28028654

Use of a Self-Instructional Radiographic Anatomy Module for Dental Hygiene Faculty Calibration.

PubMed

Brame, Jennifer L; AlGheithy, Demah Salem; Platin, Enrique; Mitchell, Shannon H

2017-06-01

Purpose: Dental hygiene educators often provide inconsistent instruction in clinical settings and various attempts to address the lack of consistency have been reported in the literature. The purpose of this pilot study was to determine if the use of a use of a self-instructional, radiographic anatomy (SIRA) module improved DH faculty calibration regarding the identifica-tion of normal intraoral and extraoral radiographic anatomy and whether its effect could be sustained over a period of four months. Methods: A convenience sample consisting of all dental hygiene faculty members involved in clinical instruction (N=23) at the University of North Carolina (UNC) was invited to complete the four parts of this online pilot study: a pre-test, review of the SIRA module, an immediate post-test, and a four-month follow-up post-test. Descriptive analyses, the Friedman's ANOVA, and the exact form of the Wilcoxon-Signed-Rank test were used to an-alyze the data. Level of significance was set at 0.05. Participants who did not complete all parts of the study were omitted from data analysis comparing the pre to post-test performance. Results: The pre-test response rate was 73.9% (N=17), and 88.2% (N=15) of those initial participants completed both the immediate and follow-up post-tests. Faculty completing all parts of the study consisted of: 5 full-time faculty, 5 part-time faculty, and 5 graduate teaching assistants. The Friedman's ANOVA revealed no statistically significant difference (P=0.179) in percentages of correct responses between the three tests (pre, post and follow-up). The exact form of the Wilcoxon-Signed-Rank test revealed marginal significance when comparing percent of correct responses at pre-test and immediate post-test (P=0.054), and no statistically significant difference when comparing percent of correct responses at immediate post-test and the follow-up post-test four months later (P=0.106). Conclusions: Use of a SIRA module did not significantly affect DH faculty test performance. Lack of statistical significance in the percentages of correct responses between the three tests may have been affected by the small number of participants completing all four parts of the study (N=15). Additional research is needed to identify and improve methods for faculty calibration. Copyright © 2017 The American Dental Hygienists’ Association.

Ranking metrics in gene set enrichment analysis: do they matter?

PubMed

Zyla, Joanna; Marczyk, Michal; Weiner, January; Polanska, Joanna

2017-05-12

There exist many methods for describing the complex relation between changes of gene expression in molecular pathways or gene ontologies under different experimental conditions. Among them, Gene Set Enrichment Analysis seems to be one of the most commonly used (over 10,000 citations). An important parameter, which could affect the final result, is the choice of a metric for the ranking of genes. Applying a default ranking metric may lead to poor results. In this work 28 benchmark data sets were used to evaluate the sensitivity and false positive rate of gene set analysis for 16 different ranking metrics including new proposals. Furthermore, the robustness of the chosen methods to sample size was tested. Using k-means clustering algorithm a group of four metrics with the highest performance in terms of overall sensitivity, overall false positive rate and computational load was established i.e. absolute value of Moderated Welch Test statistic, Minimum Significant Difference, absolute value of Signal-To-Noise ratio and Baumgartner-Weiss-Schindler test statistic. In case of false positive rate estimation, all selected ranking metrics were robust with respect to sample size. In case of sensitivity, the absolute value of Moderated Welch Test statistic and absolute value of Signal-To-Noise ratio gave stable results, while Baumgartner-Weiss-Schindler and Minimum Significant Difference showed better results for larger sample size. Finally, the Gene Set Enrichment Analysis method with all tested ranking metrics was parallelised and implemented in MATLAB, and is available at https://github.com/ZAEDPolSl/MrGSEA . Choosing a ranking metric in Gene Set Enrichment Analysis has critical impact on results of pathway enrichment analysis. The absolute value of Moderated Welch Test has the best overall sensitivity and Minimum Significant Difference has the best overall specificity of gene set analysis. When the number of non-normally distributed genes is high, using Baumgartner-Weiss-Schindler test statistic gives better outcomes. Also, it finds more enriched pathways than other tested metrics, which may induce new biological discoveries.

A Note on Comparing the Power of Test Statistics at Low Significance Levels.

PubMed

Morris, Nathan; Elston, Robert

2011-01-01

It is an obvious fact that the power of a test statistic is dependent upon the significance (alpha) level at which the test is performed. It is perhaps a less obvious fact that the relative performance of two statistics in terms of power is also a function of the alpha level. Through numerous personal discussions, we have noted that even some competent statisticians have the mistaken intuition that relative power comparisons at traditional levels such as α = 0.05 will be roughly similar to relative power comparisons at very low levels, such as the level α = 5 × 10 -8 , which is commonly used in genome-wide association studies. In this brief note, we demonstrate that this notion is in fact quite wrong, especially with respect to comparing tests with differing degrees of freedom. In fact, at very low alpha levels the cost of additional degrees of freedom is often comparatively low. Thus we recommend that statisticians exercise caution when interpreting the results of power comparison studies which use alpha levels that will not be used in practice.

Integrating the ACR Appropriateness Criteria Into the Radiology Clerkship: Comparison of Didactic Format and Group-Based Learning.

PubMed

Stein, Marjorie W; Frank, Susan J; Roberts, Jeffrey H; Finkelstein, Malka; Heo, Moonseong

2016-05-01

The aim of this study was to determine whether group-based or didactic teaching is more effective to teach ACR Appropriateness Criteria to medical students. An identical pretest, posttest, and delayed multiple-choice test was used to evaluate the efficacy of the two teaching methods. Descriptive statistics comparing test scores were obtained. On the posttest, the didactic group gained 12.5 points (P < .0001), and the group-based learning students gained 16.3 points (P < .0001). On the delayed test, the didactic group gained 14.4 points (P < .0001), and the group-based learning students gained 11.8 points (P < .001). The gains in scores on both tests were statistically significant for both groups. However, the differences in scores were not statistically significant comparing the two educational methods. Compared with didactic lectures, group-based learning is more enjoyable, time efficient, and equally efficacious. The choice of educational method can be individualized for each institution on the basis of group size, time constraints, and faculty availability. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Testing statistical isotropy in cosmic microwave background polarization maps

NASA Astrophysics Data System (ADS)

Rath, Pranati K.; Samal, Pramoda Kumar; Panda, Srikanta; Mishra, Debesh D.; Aluri, Pavan K.

2018-04-01

We apply our symmetry based Power tensor technique to test conformity of PLANCK Polarization maps with statistical isotropy. On a wide range of angular scales (l = 40 - 150), our preliminary analysis detects many statistically anisotropic multipoles in foreground cleaned full sky PLANCK polarization maps viz., COMMANDER and NILC. We also study the effect of residual foregrounds that may still be present in the Galactic plane using both common UPB77 polarization mask, as well as the individual component separation method specific polarization masks. However, some of the statistically anisotropic modes still persist, albeit significantly in NILC map. We further probed the data for any coherent alignments across multipoles in several bins from the chosen multipole range.

Trends in precipitation, streamflow, reservoir pool elevations, and reservoir releases in Arkansas and selected sites in Louisiana, Missouri, and Oklahoma, 1951–2011

USGS Publications Warehouse

Wagner, Daniel M.; Krieger, Joshua D.; Merriman, Katherine R.

2014-01-01

The U.S. Geological Survey (USGS) and the U.S. Army Corps of Engineers (USACE) conducted a statistical analysis of trends in precipitation, streamflow, reservoir pool elevations, and reservoir releases in Arkansas and selected sites in Louisiana, Missouri, and Oklahoma for the period 1951–2011. The Mann-Kendall test was used to test for trends in annual and seasonal precipitation, annual and seasonal streamflows of 42 continuous-record USGS streamflow-gaging stations, annual pool elevations and releases from 16 USACE reservoirs, and annual releases from 11 dams on the Arkansas River. A statistically significant (p≤0.10) upward trend was observed in annual precipitation for the State, with a Sen slope of approximately 0.10 inch per year. Autumn and winter were the only seasons that had statistically significant trends in precipitation. Five of six physiographic sections and six of seven 4-digit hydrologic unit code (HUC) regions in Arkansas had statistically significant upward trends in autumn precipitation, with Sen slopes of approximately 0.06 to 0.10 inch per year. Sixteen sites had statistically significant upward trends in the annual mean daily streamflow and were located on streams that drained regions with statistically significant upward trends in annual precipitation. Expected annual rates of change corresponding to statistically significant trends in annual mean daily streamflows, which ranged from 0.32 to 0.88 percent, were greater than those corresponding to regions with statistically significant upward trends in annual precipitation, which ranged from 0.19 to 0.28 percent, suggesting that the observed trends in regional annual precipitation do not fully account for the observed trends in annual mean daily streamflows. Trends in annual maximum daily streamflows were similar to trends in the annual mean daily streamflows but were only statistically significant at seven sites. There were more statistically significant trends (28 of 42 sites) in the annual minimum daily streamflows than in the annual means or maximums. Statistically significant trends in the annual minimum daily streamflows were upward at 18 sites and downward at 10 sites. Despite autumn being the only season that had statistically significant upward trends in seasonal precipitation, statistically significant upward trends in seasonal mean streamflows occurred in every season but spring. Trends in the annual mean, maximum, and minimum daily pool elevations of USACE reservoirs were consistent between metrics for reservoirs in the White, Arkansas, and Ouachita River watersheds, while trends varied between metrics at DeQueen Lake, Millwood Lake, and Lake Chicot. Most of the statistically significant trends in pool elevation metrics were upward and gradual—Sen slopes were less than 0.37 foot per year—and were likely the result of changes in reservoir regulation plans. Trends in the annual mean and maximum daily releases from USACE reservoirs were generally upward in all HUC regions. There were few statistically significant trends in the annual mean daily releases because the reservoirs are operated to maintain a regulation stage at a downstream site according to guidelines set forth in the regulation plans of the reservoirs. The annual number of low-flow days was both increasing and decreasing for reservoirs in northern Arkansas and southern Missouri and generally increasing for reservoirs in southern Arkansas.

Investigating the relationship between foveal morphology and refractive error in a population with infantile nystagmus syndrome.

PubMed

Healey, Natasha; McLoone, Eibhlin; Mahon, Gerald; Jackson, A Jonathan; Saunders, Kathryn J; McClelland, Julie F

2013-04-26

We explored associations between refractive error and foveal hypoplasia in infantile nystagmus syndrome (INS). We recruited 50 participants with INS (albinism n = 33, nonalbinism infantile nystagmus [NAIN] n = 17) aged 4 to 48 years. Cycloplegic refractive error and logMAR acuity were obtained. Spherical equivalent (SER), most ametropic meridian (MAM) refractive error, and better eye acuity (VA) were used for analyses. High resolution spectral-domain optical coherence tomography (SD-OCT) was used to obtain foveal scans, which were graded using the Foveal Hypoplasia Grading Scale. Associations between grades of severity of foveal hypoplasia, and refractive error and VA were explored. Participants with more severe foveal hypoplasia had significantly higher MAMs and SERs (Kruskal-Wallis H test P = 0.005 and P = 0.008, respectively). There were no statistically significant associations between foveal hypoplasia and cylindrical refractive error (Kruskal-Wallis H test P = 0.144). Analyses demonstrated significant differences between participants with albinism or NAIN in terms of SER and MAM (Mann-Whitney U test P = 0.001). There were no statistically significant differences between astigmatic errors between participants with albinism and NAIN. Controlling for the effects of albinism, results demonstrated no significant associations between SER, and MAM and foveal hypoplasia (partial correlation P > 0.05). Poorer visual acuity was associated statistically significantly with more severe foveal hypoplasia (Kruskal-Wallis H test P = 0.001) and with a diagnosis of albinism (Mann-Whitney U test P = 0.001). Increasing severity of foveal hypoplasia is associated with poorer VA, reflecting reduced cone density in INS. Individuals with INS also demonstrate a significant association between more severe foveal hypoplasia and increasing hyperopia. However, in the absence of albinism, there is no significant relation between refractive outcome and degree of foveal hypoplasia, suggesting that foveal maldevelopment in isolation does not impair significantly the emmetropization process. It likely is that impaired emmetropization evidenced in the albinism group may be attributed to the whole eye effect of albinism.

Summary and trend analysis of water-quality data for the Oakes Test Area, southeastern North Dakota, 1984-2004

USGS Publications Warehouse

Ryberg, Karen R.

2007-01-01

The Oakes Test Area is operated and maintained by the Garrison Diversion Conservancy District, under a cooperative agreement with the Bureau of Reclamation, to evaluate the effectiveness and environmental consequences of irrigation. As part of the evaluation, the Bureau of Reclamation collected water-quality samples from seven sites on the James River and the Oakes Test Area. The data were summarized and examined for trends in concentration. A nonparametric statistical test was used to test whether each concentration was increasing or decreasing with time for selected physical properties and constituents, and a trend slope was estimated for each constituent at each site. Trends were examined for two time periods, 1988-2004 and 1994-2004. Results varied by site and by constituent. All sites and all constituents tested had at least one statistically significant trend in the period 1988-2004. Sulfate, total dissolved solids, nitrate, and orthophosphate have significant positive trends at multiple sites with no significant negative trend at any site. Alkalinity and arsenic have single significant positive trends. Hardness, calcium, magnesium, sodium, sodium-adsorption ratio, potassium, and chloride have both significant positive and negative trends. Ammonia has a single significant negative trend. Fewer significant trends were identified in 1994-2004, and all but one were positive. The contribution to the James River from Oakes Test Area drainage appears to have little effect on water quality in the James River.

Breast MRI background parenchymal enhancement (BPE) correlates with the risk of breast cancer.

PubMed

Telegrafo, Michele; Rella, Leonarda; Stabile Ianora, Amato Antonio; Angelelli, Giuseppe; Moschetta, Marco

2016-02-01

To investigate whether background parenchymal enhancement (BPE) and breast cancer would correlate searching for any significant difference of BPE pattern distribution in case of benign or malignant lesions. 386 patients, including 180 pre-menopausal (group 1) and 206 post-menopausal (group 2), underwent MR examination. Two radiologists evaluated MR images classifying normal BPE as minimal, mild, moderate or marked. The two groups of patients were subdivided into 3 categories based on MRI findings (negative, benign and malignant lesions). The distribution of BPE patterns within the two groups and within the three MR categories was calculated. The χ2 test was used to evaluate BPE type distribution in the three patient categories and any statistically significant correlation of BPE with lesion type was calculated. The Student t test was applied to search for any statistically significant difference between BPE type rates in group 1 and 2. The χ2 test demonstrated a statistically significant difference in the distribution of BPE types in negative patients and benign lesions as compared with malignant ones (p<0.05). A significantly higher prevalence of moderate and marked BPE was found among malignant lesions (group 1: 32% and 42%, respectively; group 2: 31% and 46%, respectively) while a predominance of minimal and mild BPE among negative patients (group 1: 60% and 36%, respectively; group 2: 68% and 32%, respectively) and benign lesions (group 1: 54% and 38%, respectively; group 2: 75% and 17%, respectively) was found. The Student t test did not show a statistically significant difference between BPE type rates in group 1 and 2 (p>0.05). Normal BPE could correlate with the risk of breast cancer being such BPE patterns as moderate and marked associated with patients with malignant lesions in both pre and post-menopausal women. Copyright © 2015 Elsevier Inc. All rights reserved.

Identification of trends in rainfall, rainy days and 24 h maximum rainfall over subtropical Assam in Northeast India

NASA Astrophysics Data System (ADS)

Jhajharia, Deepak; Yadav, Brijesh K.; Maske, Sunil; Chattopadhyay, Surajit; Kar, Anil K.

2012-01-01

Trends in rainfall, rainy days and 24 h maximum rainfall are investigated using the Mann-Kendall non-parametric test at twenty-four sites of subtropical Assam located in the northeastern region of India. The trends are statistically confirmed by both the parametric and non-parametric methods and the magnitudes of significant trends are obtained through the linear regression test. In Assam, the average monsoon rainfall (rainy days) during the monsoon months of June to September is about 1606 mm (70), which accounts for about 70% (64%) of the annual rainfall (rainy days). On monthly time scales, sixteen and seventeen sites (twenty-one sites each) witnessed decreasing trends in the total rainfall (rainy days), out of which one and three trends (seven trends each) were found to be statistically significant in June and July, respectively. On the other hand, seventeen sites witnessed increasing trends in rainfall in the month of September, but none were statistically significant. In December (February), eighteen (twenty-two) sites witnessed decreasing (increasing) trends in total rainfall, out of which five (three) trends were statistically significant. For the rainy days during the months of November to January, twenty-two or more sites witnessed decreasing trends in Assam, but for nine (November), twelve (January) and eighteen (December) sites, these trends were statistically significant. These observed changes in rainfall, although most time series are not convincing as they show predominantly no significance, along with the well-reported climatic warming in monsoon and post-monsoon seasons may have implications for human health and water resources management over bio-diversity rich Northeast India.

[Descriptive analysis of work and trends in anaesthesiology from 2005 to 2006: quantitative and qualitative aspects of effects and evaluation of anaesthesia].

PubMed

Majstorović, Branislava M; Simić, Snezana; Milaković, Branko D; Vucović, Dragan S; Aleksić, Valentina V

2010-01-01

In anaesthesiology, economic aspects have been insufficiently studied. The aim of this paper was the assessment of rational choice of the anaesthesiological services based on the analysis of the scope, distribution, trend and cost. The costs of anaesthesiological services were counted based on "unit" prices from the Republic Health Insurance Fund. Data were analysed by methods of descriptive statistics and statistical significance was tested by Student's t-test and chi2-test. The number of general anaesthesia was higher and average time of general anaesthesia was shorter, without statistical significance (t-test, p = 0.436) during 2006 compared to the previous year. Local anaesthesia was significantly higher (chi2-test, p = 0.001) in relation to planned operation in emergency surgery. The analysis of total anaesthesiological procedures revealed that a number of procedures significantly increased in ENT and MFH surgery, and ophthalmology, while some reduction was observed in general surgery, orthopaedics and trauma surgery and cardiovascular surgery (chi2-test, p = 0.000). The number of analgesia was higher than other procedures (chi2-test, p = 0.000). The structure of the cost was 24% in neurosurgery, 16% in digestive (general) surgery,14% in gynaecology and obstetrics, 13% in cardiovascular surgery and 9% in emergency room. Anaesthesiological services costs were the highest in neurosurgery, due to the length anaesthesia, and digestive surgery due to the total number of general anaesthesia performed. It is important to implement pharmacoeconomic studies in all departments, and to separate the anaesthesia services for emergency and planned operations. Disproportions between the number of anaesthesia, surgery interventions and the number of patients in surgical departments gives reason to design relation database.

Measuring an Effect Size from Dichotomized Data: Contrasted Results Whether Using a Correlation or an Odds Ratio

ERIC Educational Resources Information Center

Rousson, Valentin

2014-01-01

It is well known that dichotomizing continuous data has the effect to decrease statistical power when the goal is to test for a statistical association between two variables. Modern researchers however are focusing not only on statistical significance but also on an estimation of the "effect size" (i.e., the strength of association…

Testing for nonlinearity in time series: The method of surrogate data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Theiler, J.; Galdrikian, B.; Longtin, A.

1991-01-01

We describe a statistical approach for identifying nonlinearity in time series; in particular, we want to avoid claims of chaos when simpler models (such as linearly correlated noise) can explain the data. The method requires a careful statement of the null hypothesis which characterizes a candidate linear process, the generation of an ensemble of surrogate'' data sets which are similar to the original time series but consistent with the null hypothesis, and the computation of a discriminating statistic for the original and for each of the surrogate data sets. The idea is to test the original time series against themore » null hypothesis by checking whether the discriminating statistic computed for the original time series differs significantly from the statistics computed for each of the surrogate sets. We present algorithms for generating surrogate data under various null hypotheses, and we show the results of numerical experiments on artificial data using correlation dimension, Lyapunov exponent, and forecasting error as discriminating statistics. Finally, we consider a number of experimental time series -- including sunspots, electroencephalogram (EEG) signals, and fluid convection -- and evaluate the statistical significance of the evidence for nonlinear structure in each case. 56 refs., 8 figs.« less

Effect of Internet-Based Cognitive Apprenticeship Model (i-CAM) on Statistics Learning among Postgraduate Students.

PubMed

Saadati, Farzaneh; Ahmad Tarmizi, Rohani; Mohd Ayub, Ahmad Fauzi; Abu Bakar, Kamariah

2015-01-01

Because students' ability to use statistics, which is mathematical in nature, is one of the concerns of educators, embedding within an e-learning system the pedagogical characteristics of learning is 'value added' because it facilitates the conventional method of learning mathematics. Many researchers emphasize the effectiveness of cognitive apprenticeship in learning and problem solving in the workplace. In a cognitive apprenticeship learning model, skills are learned within a community of practitioners through observation of modelling and then practice plus coaching. This study utilized an internet-based Cognitive Apprenticeship Model (i-CAM) in three phases and evaluated its effectiveness for improving statistics problem-solving performance among postgraduate students. The results showed that, when compared to the conventional mathematics learning model, the i-CAM could significantly promote students' problem-solving performance at the end of each phase. In addition, the combination of the differences in students' test scores were considered to be statistically significant after controlling for the pre-test scores. The findings conveyed in this paper confirmed the considerable value of i-CAM in the improvement of statistics learning for non-specialized postgraduate students.

Use and effect of clinical photographic records on the motivation and oral hygiene practices of a group of mentally handicapped adults.

PubMed

Bickley, S R; Shaw, L; Shaw, M J

1990-01-01

A study was undertaken to test the hypothesis that clinical photographic records can be used to motivate oral hygiene performance in mentally handicapped adults. Plaque reduction over the period of the study was shown to be higher in the test group than the control group but differences between the test and control groups were not statistically significant. The small numbers involved (29) and the difficulties in matching subjects may have mitigated against demonstrating a statistically significant difference between the two groups. All participants demonstrated high levels of toothbrushing ability during the practical aspects of the study but this was not maintained through daily oral hygiene practices in the majority of subjects.

Correlation between Na/K ratio and electron densities in blood samples of breast cancer patients.

PubMed

Topdağı, Ömer; Toker, Ozan; Bakırdere, Sezgin; Bursalıoğlu, Ertuğrul Osman; Öz, Ersoy; Eyecioğlu, Önder; Demir, Mustafa; İçelli, Orhan

2018-05-31

The main purpose of this study was to investigate the relationship between the electron densities and Na/K ratio which has important role in breast cancer disease. Determinations of sodium and potassium concentrations in blood samples performed with inductive coupled plasma-atomic emission spectrometry. Electron density values of blood samples were determined via ZXCOM. Statistical analyses were performed for electron densities and Na/K ratio including Kolmogorov-Smirnov normality tests, Spearman's rank correlation test and Mann-Whitney U test. It was found that the electron densities significantly differ between control and breast cancer groups. In addition, statistically significant positive correlation was found between the electron density and Na/K ratios in breast cancer group.

Demineralization of resin-sealed enamel by soft drinks in a clinically relevant pH cycling model.

PubMed

Bartels, Agata A; Evans, Carla A; Viana, Grace; Bedran-Russo, Ana K

2016-04-01

To compare the in vitro protective effect of orthodontic sealants on the enamel demineralization under a soft drink-induced erosive challenge. The facial surfaces of bovine incisors were sectioned into 5 mm x 4 mm x 4 mm enamel blocks. Specimens were randomly assigned to three surface protection measures: control (exposed enamel), coating with Transbond XT (unfilled resin primer), or coating with Opal Seal (filled and fluoride releasing primer). Thermocycling was used to simulate aging. The specimens were pH cycled through an acidic buffer, test beverage and a neutral buffer for a total of 7 days. Test beverages included water, Diet Mountain Dew, and Coke Classic. Quantitative light-induced fluorescence (QLF) images were taken at baseline and after aging. Final QLF images were taken to evaluate the demineralization of enamel. Data were analyzed statistically using a two-way ANOVA to compare the interaction between enamel surface protection and beverages as well as one-way ANOVA to compare surface protection and the test beverage levels. A statistically significant interaction was found between the surface protected groups and the test beverage groups (P < 0.05). Statistically significant differences were found among the test beverage groups (P < 0.05) and among the surface protection groups (P < 0.05). Coke Classic went through the sealant layer resulting in high enamel demineralization. Enamel coating with Opal Seal significantly reduced the erosive attack of beverages.

A study of correlations between crude oil spot and futures markets: A rolling sample test

NASA Astrophysics Data System (ADS)

Liu, Li; Wan, Jieqiu

2011-10-01

In this article, we investigate the asymmetries of exceedance correlations and cross-correlations between West Texas Intermediate (WTI) spot and futures markets. First, employing the test statistic proposed by Hong et al. [Asymmetries in stock returns: statistical tests and economic evaluation, Review of Financial Studies 20 (2007) 1547-1581], we find that the exceedance correlations were overall symmetric. However, the results from rolling windows show that some occasional events could induce the significant asymmetries of the exceedance correlations. Second, employing the test statistic proposed by Podobnik et al. [Quantifying cross-correlations using local and global detrending approaches, European Physics Journal B 71 (2009) 243-250], we find that the cross-correlations were significant even for large lagged orders. Using the detrended cross-correlation analysis proposed by Podobnik and Stanley [Detrended cross-correlation analysis: a new method for analyzing two nonstationary time series, Physics Review Letters 100 (2008) 084102], we find that the cross-correlations were weakly persistent and were stronger between spot and futures contract with larger maturity. Our results from rolling sample test also show the apparent effects of the exogenous events. Additionally, we have some relevant discussions on the obtained evidence.

Association between Insulin Resistance and Cardiovascular Risk Factors in Polycystic Ovary Syndrome Patients.

PubMed

Wanderley, Miriam da Silva; Pereira, Lara Cristina Ribeiro; Santos, Carla Borges; Cunha, Vinícius Santos da; Neves, Mariam Viviane Jovino

2018-04-01

 To analyze the association between the indirect methods of evaluating insulin resistance (IR) and blood pressure, anthropometric and biochemical parameters in a population of polycystic ovary syndrome (PCOS) patients.  Cross-sectional study performed at the Hospital Universitário de Brasília (HUB, in the Portuguese acronym) involving PCOS patients diagnosed from January 2011 to January 2013. Four indirect methods, namely, fasting blood insulin level, fasting glucose/insulin ratio (G/I), homeostatic model-assessment-insulin resistance (HOMA-IR), and the quantitative insulin sensitivity check index (QUICKI), were used to obtain the IR diagnosis. The data were analyzed using the test of proportions, the Chi-square test, and Fisher exact test, when indicated.  Out of the 83 patients assessed, aged 28.79 ± 5.85, IR was found in 51.81-66.2% of them using the G/I ratio and the QUICKI, respectively. The test of proportions did not show a significant difference between the methods analyzed. The proportion of IR diagnoses was statistically higher in obese women than in women with normal body mass index (BMI). We observed a statistically significant association between all the methods for diagnosing IR and BMI, waist circumference (WC) and lipid accumulation product (LAP). With regards to arterial hypertension (AH), we observed a significant association according to three methods, with the exception of the ratio G/I.  Insulin resistance prevalence varied according to the diagnostic method employed, with no statistical difference between them. The proportion of IR diagnoses was statistically higher in obese women than in women with normal BMI. We observed a significant association between IR and WC, BMI, LAP, as well as dyslipidemia and AH in a high proportion of patients. Thieme Revinter Publicações Ltda Rio de Janeiro, Brazil.

Is it possible to shorten examination time in posture control studies?

PubMed

Faraldo García, Ana; Soto Varela, Andrés; Santos Pérez, Sofía

2015-01-01

The sensory organization test (SOT) is the gold-standard test for the study of postural control with posturographic platforms. Three registers of Conditions 3, 4, 5 and 6 are conducted to find an arithmetic mean of the 3, with the time that this entails. The aim of this study was to determine whether a single record for each SOT condition would give us the same information as the arithmetic mean of the 3 recordings used until now. 100 healthy individuals who performed a sensory organisation test in the Smart Balance Master(®) Neurocom platform. For the statistical analysis we used the Wilcoxon test for nonparametric variables and dependent t-student for paired samples for parametric variables (P<.05). When comparing the scores on the first record with the average of the 3 records, we found statistically significant differences for the 4 conditions (P<0.05). Comparing the first record to the second record also yielded statistically significant differences in the 4 conditions (P<.05). Upon comparing the second record with the third, however, we found differences in only Condition 5, with the significance being borderline (P=.04). Finally, comparing the average of the first and second record with the average of the 3 records, we also found statistically significant differences for the 4 conditions (P<.05). Using only 1 or 2 records from each of the conditions on the SOT does not give us the same information as the arithmetic average of the 3 records used until now. Copyright © 2014 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Patología Cérvico-Facial. All rights reserved.

Evaluation of interactive teaching for undergraduate medical students using a classroom interactive response system in India.

PubMed

Datta, Rakesh; Datta, Karuna; Venkatesh, M D

2015-07-01

The classical didactic lecture has been the cornerstone of the theoretical undergraduate medical education. Their efficacy however reduces due to reduced interaction and short attention span of the students. It is hypothesized that the interactive response pad obviates some of these drawbacks. The aim of this study was to evaluate the effectiveness of an interactive response system by comparing it with conventional classroom teaching. A prospective comparative longitudinal study was conducted on 192 students who were exposed to either conventional or interactive teaching over 20 classes. Pre-test, Post-test and retentions test (post 8-12 weeks) scores were collated and statistically analysed. An independent observer measured number of student interactions in each class. Pre-test scores from both groups were similar (p = 0.71). There was significant improvement in both post test scores when compared to pre-test scores in either method (p < 0.001). The interactive post-test score was better than conventional post test score (p < 0.001) by 8-10% (95% CI-difference of means - 8.2%-9.24%-10.3%). The interactive retention test score was better than conventional retention test score (p < 0.001) by 15-18% (95% CI-difference of means - 15.0%-16.64%-18.2%). There were 51 participative events in the interactive group vs 25 in the conventional group. The Interactive Response Pad method was efficacious in teaching. Students taught with the interactive method were likely to score 8-10% higher (statistically significant) in the immediate post class time and 15-18% higher (statistically significant) after 8-12 weeks. The number of student-teacher interactions increases when using the interactive response pads.

Differences in Mucociliary activity of volunteers undergoing Ramadan versus Nineveh fasting.

PubMed

Develioglu, Omer Necati; Sirazi, Sait; Topak, Murat; Purisa, Sevim; Kulekci, Mehmet

2013-05-01

This study, aimed to evaluate the difference in mucociliary clearance among volunteers who underwent Ramadan versus Nineveh fasting regimens as well as the difference between the fasting period and 4 weeks following the fasting period in both groups. In this study, two different fasting groups were established: Ramadan (fasting for an average of 15 h for 29 consecutive days, n = 40) and Nineveh (60 h of nonstop fasting, n = 26). Subjects in each group underwent saccharin testing twice: at the end of the fasting period prior to resumption of eating and at 4 weeks after the end of Ramadan or Nineveh fasting. Statistical analysis was performed using the Mann-Whitney U-test, Wilcoxon, Chi-square, and paired t test. A p value less than 0.05 was considered statistically significant. Forty subjects who underwent Ramadan fasting and 26 subjects who underwent Nineveh fasting were included in this study. Of the 66 study participants, 34 (51.5 %) were men and 32 (48.5 %) were women. Their median age was 31 years (range 17-70 years) for Nineveh fasting subjects and 40 years (range 17-70 years) for Ramadan fasting subjects. Chi-square tests revealed no significant difference between the Ramadan and Nineveh fasting groups in gender (p = 0.418), and the Mann-Whitney U-test showed no difference in age. A statistically significant difference was found in the mucociliary clearance time between the Nineveh fasting and non-fasting periods (p = 0.013). Using Wilcoxon signed-rank tests, we found no significant difference in the mucociliary clearance time between the Ramadan fasting and control (4 weeks after the fasting period) periods (p = 0.121). The percentage difference between the fasting and control periods was similar between groups and was not statistically significant for the Ramadan and Nineveh fasting groups (p = 0.086). The results of the present study indicated that long-term fasting with hypohydration contributed to the deterioration of nasal mucociliary clearance. Our data indicate that optimal hydration, sleep patterns, and fasting times contribute to proper mucociliary clearance.

Ridge preservation using a composite bone graft and a bioabsorbable membrane with and without primary wound closure: a comparative clinical trial.

PubMed

Engler-Hamm, Daniel; Cheung, Wai S; Yen, Alec; Stark, Paul C; Griffin, Terrence

2011-03-01

The aim of this single-masked, randomized controlled clinical trial is to compare hard and soft tissue changes after ridge preservation performed with (control, RPc) and without (test, RPe) primary soft tissue closure in a split-mouth design. Eleven patients completed this 6-month trial. Extraction and ridge preservation were performed using a composite bone graft of inorganic bovine-derived hydroxyapatite matrix and cell binding peptide P-15 (ABM/P-15), demineralized freeze-dried bone allograft, and a copolymer bioabsorbable membrane. Primary wound closure was achieved on the control sites (RPc), whereas test sites (RPe) left the membrane exposed. Pocket probing depth on adjacent teeth, repositioning of the mucogingival junction, bone width, bone fill, and postoperative discomfort were assessed. Bone cores were obtained for histological examination. Intragroup analyses for both groups demonstrated statistically significant mean reductions in probing depth (RPc: 0.42 mm, P = 0.012; RPe: 0.25 mm, P = 0.012) and bone width (RPc: 3 mm, P = 0.002; RPe: 3.42 mm, P <0.001). However, intergroup analysis did not find these parameters to be statistically different at 6 months. The test group showed statistically significant mean change in bone fill (7.21 mm; P <0.001). Compared to the control group, the test group showed statistically significant lower mean postoperative discomfort (RPc 4 versus RPe 2; P = 0.002). Histomorphometric analysis showed presence of 0% to 40% of ABM/P-15 and 5% to 20% of new bone formation in both groups. Comparison of clinical variables between the two groups at 6 months revealed that the mucogingival junction was statistically significantly more coronally displaced in the control group than in the test group, with a mean of 3.83 mm versus 1.21 mm (P = 0.002). Ridge preservation without flap advancement preserves more keratinized tissue and has less postoperative discomfort and swelling. Although ridge preservation is performed with either method, ≈27% to 30% of bone width is lost.

Potential errors and misuse of statistics in studies on leakage in endodontics.

PubMed

Lucena, C; Lopez, J M; Pulgar, R; Abalos, C; Valderrama, M J

2013-04-01

To assess the quality of the statistical methodology used in studies of leakage in Endodontics, and to compare the results found using appropriate versus inappropriate inferential statistical methods. The search strategy used the descriptors 'root filling' 'microleakage', 'dye penetration', 'dye leakage', 'polymicrobial leakage' and 'fluid filtration' for the time interval 2001-2010 in journals within the categories 'Dentistry, Oral Surgery and Medicine' and 'Materials Science, Biomaterials' of the Journal Citation Report. All retrieved articles were reviewed to find potential pitfalls in statistical methodology that may be encountered during study design, data management or data analysis. The database included 209 papers. In all the studies reviewed, the statistical methods used were appropriate for the category attributed to the outcome variable, but in 41% of the cases, the chi-square test or parametric methods were inappropriately selected subsequently. In 2% of the papers, no statistical test was used. In 99% of cases, a statistically 'significant' or 'not significant' effect was reported as a main finding, whilst only 1% also presented an estimation of the magnitude of the effect. When the appropriate statistical methods were applied in the studies with originally inappropriate data analysis, the conclusions changed in 19% of the cases. Statistical deficiencies in leakage studies may affect their results and interpretation and might be one of the reasons for the poor agreement amongst the reported findings. Therefore, more effort should be made to standardize statistical methodology. © 2012 International Endodontic Journal.

When Null Hypothesis Significance Testing Is Unsuitable for Research: A Reassessment.

PubMed

Szucs, Denes; Ioannidis, John P A

2017-01-01

Null hypothesis significance testing (NHST) has several shortcomings that are likely contributing factors behind the widely debated replication crisis of (cognitive) neuroscience, psychology, and biomedical science in general. We review these shortcomings and suggest that, after sustained negative experience, NHST should no longer be the default, dominant statistical practice of all biomedical and psychological research. If theoretical predictions are weak we should not rely on all or nothing hypothesis tests. Different inferential methods may be most suitable for different types of research questions. Whenever researchers use NHST they should justify its use, and publish pre-study power calculations and effect sizes, including negative findings. Hypothesis-testing studies should be pre-registered and optimally raw data published. The current statistics lite educational approach for students that has sustained the widespread, spurious use of NHST should be phased out.

Nursing students' mathematic calculation skills.

PubMed

Rainboth, Lynde; DeMasi, Chris

2006-12-01

This mixed method study used a pre-test/post-test design to evaluate the efficacy of a teaching strategy in improving beginning nursing student learning outcomes. During a 4-week student teaching period, a convenience sample of 54 sophomore level nursing students were required to complete calculation assignments, taught one calculation method, and mandated to attend medication calculation classes. These students completed pre- and post-math tests and a major medication mathematic exam. Scores from the intervention student group were compared to those achieved by the previous sophomore class. Results demonstrated a statistically significant improvement from pre- to post-test and the students who received the intervention had statistically significantly higher scores on the major medication calculation exam than did the students in the control group. The evaluation completed by the intervention group showed that the students were satisfied with the method and outcome.

When Null Hypothesis Significance Testing Is Unsuitable for Research: A Reassessment

PubMed Central

Szucs, Denes; Ioannidis, John P. A.

2017-01-01

Null hypothesis significance testing (NHST) has several shortcomings that are likely contributing factors behind the widely debated replication crisis of (cognitive) neuroscience, psychology, and biomedical science in general. We review these shortcomings and suggest that, after sustained negative experience, NHST should no longer be the default, dominant statistical practice of all biomedical and psychological research. If theoretical predictions are weak we should not rely on all or nothing hypothesis tests. Different inferential methods may be most suitable for different types of research questions. Whenever researchers use NHST they should justify its use, and publish pre-study power calculations and effect sizes, including negative findings. Hypothesis-testing studies should be pre-registered and optimally raw data published. The current statistics lite educational approach for students that has sustained the widespread, spurious use of NHST should be phased out. PMID:28824397

IMMEDIATE AND FOLLOW-UP EFFECTS OF A POSTURE EDUCATION PROGRAM FOR ELEMENTARY SCHOOL STUDENTS

PubMed Central

dos Santos, Natália Brites; Sedrez, Juliana Adami; Candotti, Cláudia Tarragô; Vieira, Adriane

2017-01-01

ABSTRACT Objective: To assess the short- and medium-term effects of the posture education program (PEP) for students of elementary school regarding theoretical knowledge and posture during activities of daily living (ADLs). Methods: The sample consisted of 38 students (aged 8-12 years) in the third grade of elementary school in Porto Alegre, Rio Grande do Sul (Southern Brazil). The children were evaluated in three moments: prior to attending the PEP (pretest); after attending the PEP (post-test); and five months after the conclusion of the PEP, immediately after a learning review of four lessons (five months follow-up). The posture during ADLs and the theoretical knowledge about spine and body posture were assessed, based on specific instruments (layout for assessing the dynamic posture - LADy; and questionnaire). The Friedman test, post hoc Wilcoxon test, and Bonferroni correction were applied to identify the differences among the evaluative moments, as they are statistically significant at α<0.05. Results: No statistically significant difference was found between the post-test and follow-up concerning the theoretical knowledge. In addition, no statistically significant difference was found between post-test and follow-up in relation to ADLs; however, the performance of students was higher in the post-test and follow-up, when compared with the pretest. Conclusions: Immediately after the PEP’s conclusion, the students improved their posture in ADLs. These positive effects and the theoretical knowledge were retained in the follow-up (after the review lessons). PMID:28977326

Temporal changes in postural sway caused by ultrashort-acting hypnotics: triazolam and zolpidem.

PubMed

Nakamura, M; Ishii, M; Niwa, Y; Yamazaki, M; Ito, H

2005-01-01

Two ultrashort-acting hypnotics, triazolam 0.25 mg and zolpidem 10 mg, were studied for their effects on equilibrium function in humans. Eight healthy male subjects participated in a double-blind, placebo-controlled study after informed consent. They subjected to static equilibrium tests, oculomotor tests and an assay of drug concentrations in the blood. Zolpidem was statistically significant in postural sway in tandem stance test, as defined by parametric values of tracing sum length and polygonal area of foot pressure center measured by a gait analysis system. In the tandem stance test, triazolam was statistically significant in postural sway only as defined by the polygonal area. However, in the Romberg test, the only statistically significant difference in zolpidem use was observed in polygonal area values. Blood concentrations of triazolam and zolpidem were found to closely correlate with the extent of postural sway in both tandem stance and Romberg tests. In this study, zolpidem with minimal muscle-relaxant effect incurred imbalance more extensively than triazolam, which is known for its effect of muscle relaxation. In addition, gaze deviation nystagmus was observed only in zolpidem use in 5 of 8 subjects (62.5%). From these results, it is suggested that in the use of hypnotics, sway derives from the suppression of the central nervous system relevant to awakening rather than from muscle relaxation. The prior reference to blood concentrations of hypnotics should help improve safety care in minimizing loss of balance control and possible fall. Copyright 2005 S. Karger AG, Basel.

MR Spectroscopy to Distinguish between Supratentorial Intraventricular Subependymoma and Central Neurocytoma.

PubMed

Ueda, Fumiaki; Aburano, Hiroyuki; Ryu, Yasuji; Yoshie, Yuichi; Nakada, Mitsutoshi; Hayashi, Yutaka; Matsui, Osamu; Gabata, Toshifumi

2017-07-10

The purpose of this study was to discriminate supratentorial intraventricular subependymoma (SIS) from central neurocytoma (CNC) using magnetic resonance spectroscopy (MRS). Single-voxel proton MRS using a 1.5T or 3T MR scanner from five SISs, five CNCs, and normal controls were evaluated. They were examined using a point-resolved spectroscopy. Automatically calculated ratios comparing choline (Cho), N-acetylaspartate (NAA), myoinositol (MI), and/or glycine (Gly) to creatine (Cr) were determined. Evaluation of Cr to unsuppressed water (USW) was also performed. Mann-Whitney U test was carried out to test the significance of differences in the metabolite ratios. Detectability of lactate (Lac) and alanine (Ala) was evaluated. Although a statistically significant difference (P < 0.0001) was observed in Cho/Cr among SIS, control spectra, and CNC, no statistical difference was noted between SIS and control spectra (P = 0.11). Statistically significant differences were observed in NAA/Cr between SIS and CNC (P = 0.04) or control spectra (P < 0.0001). A statistically significant difference was observed in MI and/or Gly to Cr between SIS and control spectra (P = 0.03), and CNC and control spectra (P < 0.0006). There were no statistical differences between SIS and CNC for MI and/or Gly to Cr (P = 0.32). Significant statistical differences were found between SIS and control spectra (P < 0.0053), control spectra and CNC (P < 0.0016), and SIS and CNC (P < 0.0083) for Cr to USW. Lac inverted doublets were confirmed in two SISs. Triplets of Lac and Ala were detected in four spectra of CNC. The present study showed that MRS can be useful in discriminating SIS from CNC.

The extended statistical analysis of toxicity tests using standardised effect sizes (SESs): a comparison of nine published papers.

PubMed

Festing, Michael F W

2014-01-01

The safety of chemicals, drugs, novel foods and genetically modified crops is often tested using repeat-dose sub-acute toxicity tests in rats or mice. It is important to avoid misinterpretations of the results as these tests are used to help determine safe exposure levels in humans. Treated and control groups are compared for a range of haematological, biochemical and other biomarkers which may indicate tissue damage or other adverse effects. However, the statistical analysis and presentation of such data poses problems due to the large number of statistical tests which are involved. Often, it is not clear whether a "statistically significant" effect is real or a false positive (type I error) due to sampling variation. The author's conclusions appear to be reached somewhat subjectively by the pattern of statistical significances, discounting those which they judge to be type I errors and ignoring any biomarker where the p-value is greater than p = 0.05. However, by using standardised effect sizes (SESs) a range of graphical methods and an over-all assessment of the mean absolute response can be made. The approach is an extension, not a replacement of existing methods. It is intended to assist toxicologists and regulators in the interpretation of the results. Here, the SES analysis has been applied to data from nine published sub-acute toxicity tests in order to compare the findings with those of the author's. Line plots, box plots and bar plots show the pattern of response. Dose-response relationships are easily seen. A "bootstrap" test compares the mean absolute differences across dose groups. In four out of seven papers where the no observed adverse effect level (NOAEL) was estimated by the authors, it was set too high according to the bootstrap test, suggesting that possible toxicity is under-estimated.

OSPAR standard method and software for statistical analysis of beach litter data.

PubMed

Schulz, Marcus; van Loon, Willem; Fleet, David M; Baggelaar, Paul; van der Meulen, Eit

2017-09-15

The aim of this study is to develop standard statistical methods and software for the analysis of beach litter data. The optimal ensemble of statistical methods comprises the Mann-Kendall trend test, the Theil-Sen slope estimation, the Wilcoxon step trend test and basic descriptive statistics. The application of Litter Analyst, a tailor-made software for analysing the results of beach litter surveys, to OSPAR beach litter data from seven beaches bordering on the south-eastern North Sea, revealed 23 significant trends in the abundances of beach litter types for the period 2009-2014. Litter Analyst revealed a large variation in the abundance of litter types between beaches. To reduce the effects of spatial variation, trend analysis of beach litter data can most effectively be performed at the beach or national level. Spatial aggregation of beach litter data within a region is possible, but resulted in a considerable reduction in the number of significant trends. Copyright © 2017 Elsevier Ltd. All rights reserved.

Elemental, microstructural, and mechanical characterization of high gold orthodontic brackets after intraoral aging.

PubMed

Hersche, Sepp; Sifakakis, Iosif; Zinelis, Spiros; Eliades, Theodore

2017-02-01

The purpose of the present study was to investigate the elemental composition, the microstructure, and the selected mechanical properties of high gold orthodontic brackets after intraoral aging. Thirty Incognito™ (3M Unitek, Bad Essen, Germany) lingual brackets were studied, 15 brackets as received (control group) and 15 brackets retrieved from different patients after orthodontic treatment. The surface of the wing area was examined by scanning electron microscopy (SEM). Backscattered electron imaging (BEI) was performed, and the elemental composition was determined by X-ray EDS analysis (EDX). After appropriate metallographic preparation, the mechanical properties tested were Martens hardness (HM), indentation modulus (EIT), elastic index (ηIT), and Vickers hardness (HV). These properties were determined employing instrumented indentation testing (IIT) with a Vickers indenter. The results were statistically analyzed by unpaired t-test (α=0.05). There were no statistically significant differences evidenced in surface morphology and elemental content between the control and the experimental group. These two groups of brackets showed no statistically significant difference in surface morphology. Moreover, the mean values of HM, EIT, ηIT, and HV did not reach statistical significance between the groups (p>0.05). Under the limitations of this study, it may be concluded that the surface elemental content and microstructure as well as the evaluated mechanical properties of the Incognito™ lingual brackets remain unaffected by intraoral aging.

The Influence of 16-year-old Students' Gender, Mental Abilities, and Motivation on their Reading and Drawing Submicrorepresentations Achievements

NASA Astrophysics Data System (ADS)

Devetak, Iztok; Aleksij Glažar, Saša

2010-08-01

Submicrorepresentations (SMRs) are a powerful tool for identifying misconceptions of chemical concepts and for generating proper mental models of chemical phenomena in students' long-term memory during chemical education. The main purpose of the study was to determine which independent variables (gender, formal reasoning abilities, visualization abilities, and intrinsic motivation for learning chemistry) have the maximum influence on students' reading and drawing SMRs. A total of 386 secondary school students (aged 16.3 years) participated in the study. The instruments used in the study were: test of Chemical Knowledge, Test of Logical Thinking, two tests of visualization abilities Patterns and Rotations, and questionnaire on Intrinsic Motivation for Learning Science. The results show moderate, but statistically significant correlations between students' intrinsic motivation, formal reasoning abilities and chemical knowledge at submicroscopic level based on reading and drawing SMRs. Visualization abilities are not statistically significantly correlated with students' success on items that comprise reading or drawing SMRs. It can be also concluded that there is a statistically significant difference between male and female students in solving problems that include reading or drawing SMRs. Based on these statistical results and content analysis of the sample problems, several educational strategies can be implemented for students to develop adequate mental models of chemical concepts on all three levels of representations.

The Need for Nuance in the Null Hypothesis Significance Testing Debate

ERIC Educational Resources Information Center

Häggström, Olle

2017-01-01

Null hypothesis significance testing (NHST) provides an important statistical toolbox, but there are a number of ways in which it is often abused and misinterpreted, with bad consequences for the reliability and progress of science. Parts of contemporary NHST debate, especially in the psychological sciences, is reviewed, and a suggestion is made…

A Comparison of Two Tests for the Significance of a Mean Vector.

DTIC Science & Technology

1978-01-01

rejected as soon as a component test in the sequence shows significance . It is well. known (3’. Roy 1958; Roy, Gnanadesikan and Srivastava 1971 (p...confidence bounds ” , Annals of Mathematical Statistics, 29, 491—503. (14] Roy, S.N., Gnanadesikan , R., and Srivastava, J.N. (1971). Analysis and

Thou Shalt Not Bear False Witness against Null Hypothesis Significance Testing

ERIC Educational Resources Information Center

García-Pérez, Miguel A.

2017-01-01

Null hypothesis significance testing (NHST) has been the subject of debate for decades and alternative approaches to data analysis have been proposed. This article addresses this debate from the perspective of scientific inquiry and inference. Inference is an inverse problem and application of statistical methods cannot reveal whether effects…

Effect of Chocobar Ice Cream Containing Bifidobacterium on Salivary Streptococcus mutans and Lactobacilli: A Randomised Controlled Trial.

PubMed

Nagarajappa, Ramesh; Daryani, Hemasha; Sharda, Archana J; Asawa, Kailash; Batra, Mehak; Sanadhya, Sudhanshu; Ramesh, Gayathri

2015-01-01

To examine the effect of chocobar ice cream containing bifidobacteria on salivary mutans streptococci and lactobacilli. A double-blind, randomised controlled trial was conducted with 30 subjects (18 to 22 years of age) divided into 2 groups, test (chocobar ice cream with probiotics) and control (chocobar ice cream without probiotics). The subjects were instructed to eat the allotted chocobar ice cream once daily for 18 days. Saliva samples collected at intervals were cultured on Mitis Salivarius agar and Rogosa agar and examined for salivary mutans streptococci and lactobacilli, respectively. The Mann-Whitney U-test, Friedman and Wilcoxon signed-rank tests were used for statistical analysis. Postingestion in the test group, a statistically significant reduction (p < 0.05) of salivary mutans streptococci was recorded, but a non-significant trend was seen for lactobacilli. Significant differences were was also observed between follow-ups. Short-term daily ingestion of ice cream containing probiotic bifidobacteria may reduce salivary levels of mutans streptococci in young adults.

Prevalence of upper airway obstruction in patients with apparently asymptomatic euthyroid multi nodular goitre

PubMed Central

Menon, Sunil K.; Jagtap, Varsha S.; Sarathi, Vijaya; Lila, Anurag R.; Bandgar, Tushar R.; Menon, Padmavathy S; Shah, Nalini S.

2011-01-01

Aims: To study the prevalence of upper airway obstruction (UAO) in “apparently asymptomatic” patients with euthyroid multinodular goitre (MNG) and find correlation between clinical features, UAO on pulmonary function test (PFT) and tracheal narrowing on computerised tomography (CT). Materials and Methods: Consecutive patients with apparently asymptomatic euthyroid MNG attending thyroid clinic in a tertiary centre underwent clinical examination to elicit features of UAO, PFT, and CT of neck and chest. Statistical Analysis Used: Statistical analysis was done with SPSS version 11.5 using paired t-test, Chi square test, and Fisher's exact test. P value of <0.05 was considered to be significant. Results: Fifty-six patients (52 females and four males) were studied. The prevalence of UAO (PFT) and significant tracheal narrowing (CT) was 14.3%. and 9.3%, respectively. Clinical features failed to predict UAO or significant tracheal narrowing. Tracheal narrowing (CT) did not correlate with UAO (PFT). Volume of goitre significantly correlated with degree of tracheal narrowing. Conclusions: Clinical features do not predict UAO on PFT or tracheal narrowing on CT in apparently asymptomatic patients with euthyroid MNG. PMID:21966649

Visual Performance on the Small Letter Contrast Test: Effects of Aging, Low Luminance and Refractive Error

DTIC Science & Technology

2000-08-01

luminance performance and aviation, many aviators develop ametropias refractive error having comparable effects on during their careers. We were... statistically (0.04 logMAR, the non-aviator group. Separate investigators at p=0.01), but not clinically significant (ə/2 line different research facilities... statistically significant (0.11 ± 0.1 logCS, t=4.0, sensitivity on the SLCT decreased for the aviator pɘ.001), yet there is significant overlap group at a

How conservative is Fisher's exact test? A quantitative evaluation of the two-sample comparative binomial trial.

PubMed

Crans, Gerald G; Shuster, Jonathan J

2008-08-15

The debate as to which statistical methodology is most appropriate for the analysis of the two-sample comparative binomial trial has persisted for decades. Practitioners who favor the conditional methods of Fisher, Fisher's exact test (FET), claim that only experimental outcomes containing the same amount of information should be considered when performing analyses. Hence, the total number of successes should be fixed at its observed level in hypothetical repetitions of the experiment. Using conditional methods in clinical settings can pose interpretation difficulties, since results are derived using conditional sample spaces rather than the set of all possible outcomes. Perhaps more importantly from a clinical trial design perspective, this test can be too conservative, resulting in greater resource requirements and more subjects exposed to an experimental treatment. The actual significance level attained by FET (the size of the test) has not been reported in the statistical literature. Berger (J. R. Statist. Soc. D (The Statistician) 2001; 50:79-85) proposed assessing the conservativeness of conditional methods using p-value confidence intervals. In this paper we develop a numerical algorithm that calculates the size of FET for sample sizes, n, up to 125 per group at the two-sided significance level, alpha = 0.05. Additionally, this numerical method is used to define new significance levels alpha(*) = alpha+epsilon, where epsilon is a small positive number, for each n, such that the size of the test is as close as possible to the pre-specified alpha (0.05 for the current work) without exceeding it. Lastly, a sample size and power calculation example are presented, which demonstrates the statistical advantages of implementing the adjustment to FET (using alpha(*) instead of alpha) in the two-sample comparative binomial trial. 2008 John Wiley & Sons, Ltd

An Evaluation of the Euroncap Crash Test Safety Ratings in the Real World

PubMed Central

Segui-Gomez, Maria; Lopez-Valdes, Francisco J.; Frampton, Richard

2007-01-01

We investigated whether the rating obtained in the EuroNCAP test procedures correlates with injury protection to vehicle occupants in real crashes using data in the UK Cooperative Crash Injury Study (CCIS) database from 1996 to 2005. Multivariate Poisson regression models were developed, using the Abbreviated Injury Scale (AIS) score by body region as the dependent variable and the EuroNCAP score for that particular body region, seat belt use, mass ratio and Equivalent Test Speed (ETS) as independent variables. Our models identified statistically significant relationships between injury severity and safety belt use, mass ratio and ETS. We could not identify any statistically significant relationships between the EuroNCAP body region scores and real injury outcome except for the protection to pelvis-femur-knee in frontal impacts where scoring “green” is significantly better than scoring “yellow” or “red”.

Statistical significance of combinatorial regulations

PubMed Central

Terada, Aika; Okada-Hatakeyama, Mariko; Tsuda, Koji; Sese, Jun

2013-01-01

More than three transcription factors often work together to enable cells to respond to various signals. The detection of combinatorial regulation by multiple transcription factors, however, is not only computationally nontrivial but also extremely unlikely because of multiple testing correction. The exponential growth in the number of tests forces us to set a strict limit on the maximum arity. Here, we propose an efficient branch-and-bound algorithm called the “limitless arity multiple-testing procedure” (LAMP) to count the exact number of testable combinations and calibrate the Bonferroni factor to the smallest possible value. LAMP lists significant combinations without any limit, whereas the family-wise error rate is rigorously controlled under the threshold. In the human breast cancer transcriptome, LAMP discovered statistically significant combinations of as many as eight binding motifs. This method may contribute to uncover pathways regulated in a coordinated fashion and find hidden associations in heterogeneous data. PMID:23882073

Fracture load and failure analysis of zirconia single crowns veneered with pressed and layered ceramics after chewing simulation.

PubMed

Stawarczyk, Bogna; Ozcan, Mutlu; Roos, Malgorzata; Trottmann, Albert; Hämmerle, Christoph H F

2011-01-01

This study determined the fracture load of zirconia crowns veneered with four overpressed and four layered ceramics after chewing simulation. The veneered zirconia crowns were cemented and subjected to chewing cycling. Subsequently, the specimens were loaded at an angle of 45° in a Universal Testing Machine to determine the fracture load. One-way ANOVA, followed by a post-hoc Scheffé test, t-test and Weibull statistic were performed. Overpressed crowns showed significantly lower fracture load (543-577 N) compared to layered ones (805-1067 N). No statistical difference was found between the fracture loads within the overpressed group. Within the layered groups, LV (1067 N) presented significantly higher results compared to LC (805 N). The mean values of all other groups were not significantly different. Single zirconia crowns veneered with overpressed ceramics exhibited lower fracture load than those of the layered ones after chewing simulation.

Source credibility and evidence format: examining the effectiveness of HIV/AIDS messages for young African Americans.

PubMed

Major, Lesa Hatley; Coleman, Renita

2012-01-01

Using experimental methodology, this study tests the effectiveness of HIV/AIDS prevention messages tailored specifically to college-aged African Americans. To test interaction effects, it intersects source role and evidence format. The authors used gain-framed and loss-framed information specific to young African Americans and HIV to test message effectiveness between statistical and emotional evidence formats, and for the first time, a statistical/emotional combination format. It tests which source--physician or minister--that young African Americans believe is more effective when delivering HIV/AIDS messages to young African Americans. By testing the interaction between source credibility and evidence format, this research expands knowledge on creating effective health messages in several major areas. Findings include a significant interaction between the role of physician and the combined statistical/emotional format. This message was rated as the most effective way to deliver HIV/AIDS prevention messages.

Balance exercise for persons with multiple sclerosis using Wii games: a randomised, controlled multi-centre study.

PubMed

Nilsagård, Ylva E; Forsberg, Anette S; von Koch, Lena

2013-02-01

The use of interactive video games is expanding within rehabilitation. The evidence base is, however, limited. Our aim was to evaluate the effects of a Nintendo Wii Fit® balance exercise programme on balance function and walking ability in people with multiple sclerosis (MS). A multi-centre, randomised, controlled single-blinded trial with random allocation to exercise or no exercise. The exercise group participated in a programme of 12 supervised 30-min sessions of balance exercises using Wii games, twice a week for 6-7 weeks. Primary outcome was the Timed Up and Go test (TUG). In total, 84 participants were enrolled; four were lost to follow-up. After the intervention, there were no statistically significant differences between groups but effect sizes for the TUG, TUGcognitive and, the Dynamic Gait Index (DGI) were moderate and small for all other measures. Statistically significant improvements within the exercise group were present for all measures (large to moderate effect sizes) except in walking speed and balance confidence. The non-exercise group showed statistically significant improvements for the Four Square Step Test and the DGI. In comparison with no intervention, a programme of supervised balance exercise using Nintendo Wii Fit® did not render statistically significant differences, but presented moderate effect sizes for several measures of balance performance.

Mass detection, localization and estimation for wind turbine blades based on statistical pattern recognition

NASA Astrophysics Data System (ADS)

Colone, L.; Hovgaard, M. K.; Glavind, L.; Brincker, R.

2018-07-01

A method for mass change detection on wind turbine blades using natural frequencies is presented. The approach is based on two statistical tests. The first test decides if there is a significant mass change and the second test is a statistical group classification based on Linear Discriminant Analysis. The frequencies are identified by means of Operational Modal Analysis using natural excitation. Based on the assumption of Gaussianity of the frequencies, a multi-class statistical model is developed by combining finite element model sensitivities in 10 classes of change location on the blade, the smallest area being 1/5 of the span. The method is experimentally validated for a full scale wind turbine blade in a test setup and loaded by natural wind. Mass change from natural causes was imitated with sand bags and the algorithm was observed to perform well with an experimental detection rate of 1, localization rate of 0.88 and mass estimation rate of 0.72.

Statistical validation of normal tissue complication probability models.

PubMed

Xu, Cheng-Jian; van der Schaaf, Arjen; Van't Veld, Aart A; Langendijk, Johannes A; Schilstra, Cornelis

2012-09-01

To investigate the applicability and value of double cross-validation and permutation tests as established statistical approaches in the validation of normal tissue complication probability (NTCP) models. A penalized regression method, LASSO (least absolute shrinkage and selection operator), was used to build NTCP models for xerostomia after radiation therapy treatment of head-and-neck cancer. Model assessment was based on the likelihood function and the area under the receiver operating characteristic curve. Repeated double cross-validation showed the uncertainty and instability of the NTCP models and indicated that the statistical significance of model performance can be obtained by permutation testing. Repeated double cross-validation and permutation tests are recommended to validate NTCP models before clinical use. Copyright © 2012 Elsevier Inc. All rights reserved.

Erratum to "Large-scale mitochondrial COI gene sequence variability reflects the complex colonization history of the invasive soft-shell clam, Mya arenaria (L.) (Bivalvia)" [Estuar. Coast. Shelf Sci. 181 (2016) 256-265

NASA Astrophysics Data System (ADS)

Lasota, Rafal; Pierscieniak, Karolina; Garcia, Pascale; Simon-Bouhet, Benoit; Wolowicz, Maciej

2017-03-01

The publisher regrets a printing error in the last paragraph in the Results section. The correct text should read as follows: Tajima's D, Fu and Li's D* and F*, and Fu's Fs were negative for all American populations, and statistically significant in most cases (Table 3). In most of the European populations the values of neutrality tests were positive, but not statistically significant. The highest positive values of neutrality tests were noted in the populations from Reykjavik (Iceland) and Dublin (Ireland) (Table 3).

Radiation detection method and system using the sequential probability ratio test

DOEpatents

Nelson, Karl E [Livermore, CA; Valentine, John D [Redwood City, CA; Beauchamp, Brock R [San Ramon, CA

2007-07-17

A method and system using the Sequential Probability Ratio Test to enhance the detection of an elevated level of radiation, by determining whether a set of observations are consistent with a specified model within a given bounds of statistical significance. In particular, the SPRT is used in the present invention to maximize the range of detection, by providing processing mechanisms for estimating the dynamic background radiation, adjusting the models to reflect the amount of background knowledge at the current point in time, analyzing the current sample using the models to determine statistical significance, and determining when the sample has returned to the expected background conditions.

Is there an association between flow diverter fish mouthing and delayed-type hypersensitivity to metals?-a case-control study.

PubMed

Kocer, Naci; Mondel, Prabath Kumar; Yamac, Elif; Kavak, Ayse; Kizilkilic, Osman; Islak, Civan

2017-11-01

Flow diverters are increasingly used in the treatment of complex and giant intracranial aneurysms. However, they are associated with complications like late aneurysmal rupture. Additionally, flow diverters show focal structural decrease in luminal diameter without any intimal hyperplasia. This resembles a "fish mouth" when viewed en face. In this pilot study, we tested the hypothesis of a possible association between flow diverter fish-mouthing and delayed-type hypersensitivity to its metal constituents. We retrospectively reviewed patient records from our center between May 2010 and November 2015. A total of nine patients had flow diverter fish mouthing. A control group of 25 patients was selected. All study participants underwent prospective patch test to detect hypersensitivity to flow diverter metal constituents. Analysis was performed using logistic regression analysis and Wilcoxon sign rank sum test. Univariate and multivariate analyses were performed to test variables to predict flow diverter fish mouthing. The association between flow diverter fish mouthing and positive patch test was not statistically significant. In multivariate analysis, history of allergy and maximum aneurysm size category was associated with flow diverter fish mouthing. This was further confirmed on Wilcoxon sign rank sum test. The study showed statistically significant association between flow diverter fish mouthing and history of contact allergy and a small aneurysmal size. Further large-scale studies are needed to detect a statistically significant association between flow diverter fish mouthing and patch test. We recommend early and more frequent follow-up imaging in patients with contact allergy to detect flow diverter fish mouthing and its subsequent evolution.

[Comparison of thromboelastography and routine coagulation tests for evaluation of blood coagulation function in patients].

PubMed

Chen, Guan-Yi; Ou Yang, Xi-Lin; Wu, Jing-Hui; Wang, Li-Hua; Yang, Jin-Hua; Gu, Li-Nan; Lu, Zhu-Jie; Zhao, Xiao-Zi

2015-04-01

To investigate the correlation and consistency between thromboelastography(TEG) and routine coagulation tests, and to evaluate the value of the two methods in determining the blood coagulation of patients. The TEG, routine coagulation tests and platelet counts of 182 patients from the Intensive Care Unit(ICU) and Department of Gastroenterology in our hospital from January to September 2014 were performed and analyzed retrospectively for their correlation, Kappa identity test analysis and chi-square test, and the diagnostic sensitivity and specificity of both methods in the patients with bleeding were evaluated. The TEG R time and PT, R time and APTT showed a linear dependence (P<0.01). The relationship between the TEG K value, α-Angle, MA and Fibrinogen showed a linear dependence (P<0.001). And the relationship between the TEG K value, α-Angle, MA and the platelet count were in a linear dependent way (P<0.001). The Kappa values of the TEG R time with PT and APTT were 0.038 (P>0.05) and 0.061 (P>0.05), respectively. The chi-square test values of the TEG R time with PT and APTT were 35.309 (P<0.001) and 15.848 (P<0.001), respectively. The Fibrinogen and the TEG K value, α-Angle, MA value had statistical significance (P<0.001), with a Kappa value of 0.323, 0.288 and 0.427, respectively. The chi-square test values between Fibrinogen and the TEG K value, α-Angle, MA value were not statistically significant, with X2=1.091 (P=0.296), X2=1.361 (P=0.243), X2=0.108 (P=0.742). The Kappa values of the platelet count and the TEG K value, α-Angle, MA value were 0.379, 0.208 and 0.352, respectively, which were also statistically significant difference (P<0.001). The chi-square test values between the platelet count and the TEG K value, α-Angle, MA value showed a statistically significant difference (P<0.001), with X2=37.5, X2=37.23, X2=26.630. The diagnostic sensitivity of the two methods for the patients with bleeding was less than 50%. There was a significant correlation between some TEG parameters and routine coagulation tests, but the consistency is weak. Moreover, the diagnostic sensitivity of two methods in the patients with bleeding is low. It was concluded that the TEG cannot replace the conventional coagulation tests, and the preferable method remains uncertain which could reflect the risk of bleeding.

On the assessment of the added value of new predictive biomarkers.

PubMed

Chen, Weijie; Samuelson, Frank W; Gallas, Brandon D; Kang, Le; Sahiner, Berkman; Petrick, Nicholas

2013-07-29

The surge in biomarker development calls for research on statistical evaluation methodology to rigorously assess emerging biomarkers and classification models. Recently, several authors reported the puzzling observation that, in assessing the added value of new biomarkers to existing ones in a logistic regression model, statistical significance of new predictor variables does not necessarily translate into a statistically significant increase in the area under the ROC curve (AUC). Vickers et al. concluded that this inconsistency is because AUC "has vastly inferior statistical properties," i.e., it is extremely conservative. This statement is based on simulations that misuse the DeLong et al. method. Our purpose is to provide a fair comparison of the likelihood ratio (LR) test and the Wald test versus diagnostic accuracy (AUC) tests. We present a test to compare ideal AUCs of nested linear discriminant functions via an F test. We compare it with the LR test and the Wald test for the logistic regression model. The null hypotheses of these three tests are equivalent; however, the F test is an exact test whereas the LR test and the Wald test are asymptotic tests. Our simulation shows that the F test has the nominal type I error even with a small sample size. Our results also indicate that the LR test and the Wald test have inflated type I errors when the sample size is small, while the type I error converges to the nominal value asymptotically with increasing sample size as expected. We further show that the DeLong et al. method tests a different hypothesis and has the nominal type I error when it is used within its designed scope. Finally, we summarize the pros and cons of all four methods we consider in this paper. We show that there is nothing inherently less powerful or disagreeable about ROC analysis for showing the usefulness of new biomarkers or characterizing the performance of classification models. Each statistical method for assessing biomarkers and classification models has its own strengths and weaknesses. Investigators need to choose methods based on the assessment purpose, the biomarker development phase at which the assessment is being performed, the available patient data, and the validity of assumptions behind the methodologies.

Analysis of responses of cold pressor tests on pilots and executives

NASA Technical Reports Server (NTRS)

Swaroop, R.

1977-01-01

Statistical analyses were performed to study the relationship between cold pressor test responses and certain medical attributes of a group of 81 pilots and a group of 466 executives. The important results of this study were as follows: There was a significant relationship between a subject's cold pressor test response and his profession (that is, pilot or executive). The executives' diastolic cold pressor test responses were significantly related to their medical conditions, and their families' medical conditions. Significant relationships were observed between executives' diastolic and systolic cold pressor test responses and their history of tranquilizer and cardiac drug use.

Performing Inferential Statistics Prior to Data Collection

ERIC Educational Resources Information Center

Trafimow, David; MacDonald, Justin A.

2017-01-01

Typically, in education and psychology research, the investigator collects data and subsequently performs descriptive and inferential statistics. For example, a researcher might compute group means and use the null hypothesis significance testing procedure to draw conclusions about the populations from which the groups were drawn. We propose an…

Predicting juvenile recidivism: new method, old problems.

PubMed

Benda, B B

1987-01-01

This prediction study compared three statistical procedures for accuracy using two assessment methods. The criterion is return to a juvenile prison after the first release, and the models tested are logit analysis, predictive attribute analysis, and a Burgess procedure. No significant differences are found between statistics in prediction.

Bond strength to root dentin and fluid filtration test of AH Plus/gutta-percha, EndoREZ and RealSeal systems

PubMed Central

MAHDI, Alaa Abdul; BOLAÑOS-CARMONA, Victoria; GONZALEZ-LOPEZ, Santiago

2013-01-01

Objectives To investigate the bond strength and seal ability produced by AH Plus/gutta-percha, EndoREZ and RealSeal systems to root canal dentin. Material and Methods Sixty extracted single-root human teeth, instrumented manually to size 40, were divided into three groups (n=20) according to the sealer used; G1: AH Plus, G2: EndoREZ, and G3: RealSeal sealers. After filling using the lateral condensation technique, each sealer group was randomly divided into two subgroups according to the tests applied (n=10 for µPush-out test and n=10 for fluid filtration test). A fluid filtration method was used for quantitative evaluation of apical leakage. Four 1-mm-thick slices (cervical and medium level) were obtained from each root sample and a µPush-out test was performed. Failure modes were examined under microscopy at 40x, and a one-way ANOVA was applied to analyze the permeability. Non-parametrical statistics for related (Friedman's and Wilcoxon's rank tests) or unrelated samples (Kruskal-Wallis' and Mann-Whitney's tests) allowed for comparisons of µPush-out strength values among materials at the different levels. Statistical significance was accepted for p values <.05. Results There are no significant differences among fluid filtration of the three sealers. The sealer/core material does not significantly influence the µPush-out bond strength values (F=2.49; p=0.10), although statistically significant differences were detected with regard to root level (Chi2=23.93; p<0.001). AH Plus and RealSeal obtained higher bond strength to intraradicular dentin in the medium root slices. Conclusions There are no significant differences between the permeability and global µPush-out bond strength to root canal dentin achieved by AH Plus/gutta-percha, EndoREZ and RealSeal systems. PMID:24037078

Prognostic significance of electrical alternans versus signal averaged electrocardiography in predicting the outcome of electrophysiological testing and arrhythmia-free survival

NASA Technical Reports Server (NTRS)

Armoundas, A. A.; Rosenbaum, D. S.; Ruskin, J. N.; Garan, H.; Cohen, R. J.

1998-01-01

OBJECTIVE: To investigate the accuracy of signal averaged electrocardiography (SAECG) and measurement of microvolt level T wave alternans as predictors of susceptibility to ventricular arrhythmias. DESIGN: Analysis of new data from a previously published prospective investigation. SETTING: Electrophysiology laboratory of a major referral hospital. PATIENTS AND INTERVENTIONS: 43 patients, not on class I or class III antiarrhythmic drug treatment, undergoing invasive electrophysiological testing had SAECG and T wave alternans measurements. The SAECG was considered positive in the presence of one (SAECG-I) or two (SAECG-II) of three standard criteria. T wave alternans was considered positive if the alternans ratio exceeded 3.0. MAIN OUTCOME MEASURES: Inducibility of sustained ventricular tachycardia or fibrillation during electrophysiological testing, and 20 month arrhythmia-free survival. RESULTS: The accuracy of T wave alternans in predicting the outcome of electrophysiological testing was 84% (p < 0.0001). Neither SAECG-I (accuracy 60%; p < 0.29) nor SAECG-II (accuracy 71%; p < 0.10) was a statistically significant predictor of electrophysiological testing. SAECG, T wave alternans, electrophysiological testing, and follow up data were available in 36 patients while not on class I or III antiarrhythmic agents. The accuracy of T wave alternans in predicting the outcome of arrhythmia-free survival was 86% (p < 0.030). Neither SAECG-I (accuracy 65%; p < 0.21) nor SAECG-II (accuracy 71%; p < 0.48) was a statistically significant predictor of arrhythmia-free survival. CONCLUSIONS: T wave alternans was a highly significant predictor of the outcome of electrophysiological testing and arrhythmia-free survival, while SAECG was not a statistically significant predictor. Although these results need to be confirmed in prospective clinical studies, they suggest that T wave alternans may serve as a non-invasive probe for screening high risk populations for malignant ventricular arrhythmias.

Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) scores generated from the MMPI-2 and MMPI-2-RF test booklets: internal structure comparability in a sample of criminal defendants.

PubMed

Tarescavage, Anthony M; Alosco, Michael L; Ben-Porath, Yossef S; Wood, Arcangela; Luna-Jones, Lynn

2015-04-01

We investigated the internal structure comparability of Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) scores derived from the MMPI-2 and MMPI-2-RF booklets in a sample of 320 criminal defendants (229 males and 54 females). After exclusion of invalid protocols, the final sample consisted of 96 defendants who were administered the MMPI-2-RF booklet and 83 who completed the MMPI-2. No statistically significant differences in MMPI-2-RF invalidity rates were observed between the two forms. Individuals in the final sample who completed the MMPI-2-RF did not statistically differ on demographics or referral question from those who were administered the MMPI-2 booklet. Independent t tests showed no statistically significant differences between MMPI-2-RF scores generated with the MMPI-2 and MMPI-2-RF booklets on the test's substantive scales. Statistically significant small differences were observed on the revised Variable Response Inconsistency (VRIN-r) and True Response Inconsistency (TRIN-r) scales. Cronbach's alpha and standard errors of measurement were approximately equal between the booklets for all MMPI-2-RF scales. Finally, MMPI-2-RF intercorrelations produced from the two forms yielded mostly small and a few medium differences, indicating that discriminant validity and test structure are maintained. Overall, our findings reflect the internal structure comparability of MMPI-2-RF scale scores generated from MMPI-2 and MMPI-2-RF booklets. Implications of these results and limitations of these findings are discussed. © The Author(s) 2014.

The transfer of analytical procedures.

PubMed

Ermer, J; Limberger, M; Lis, K; Wätzig, H

2013-11-01

Analytical method transfers are certainly among the most discussed topics in the GMP regulated sector. However, they are surprisingly little regulated in detail. General information is provided by USP, WHO, and ISPE in particular. Most recently, the EU emphasized the importance of analytical transfer by including it in their draft of the revised GMP Guideline. In this article, an overview and comparison of these guidelines is provided. The key to success for method transfers is the excellent communication between sending and receiving unit. In order to facilitate this communication, procedures, flow charts and checklists for responsibilities, success factors, transfer categories, the transfer plan and report, strategies in case of failed transfers, tables with acceptance limits are provided here, together with a comprehensive glossary. Potential pitfalls are described such that they can be avoided. In order to assure an efficient and sustainable transfer of analytical procedures, a practically relevant and scientifically sound evaluation with corresponding acceptance criteria is crucial. Various strategies and statistical tools such as significance tests, absolute acceptance criteria, and equivalence tests are thoroughly descibed and compared in detail giving examples. Significance tests should be avoided. The success criterion is not statistical significance, but rather analytical relevance. Depending on a risk assessment of the analytical procedure in question, statistical equivalence tests are recommended, because they include both, a practically relevant acceptance limit and a direct control of the statistical risks. However, for lower risk procedures, a simple comparison of the transfer performance parameters to absolute limits is also regarded as sufficient. Copyright © 2013 Elsevier B.V. All rights reserved.

Sequential CFAR detectors using a dead-zone limiter

NASA Astrophysics Data System (ADS)

Tantaratana, Sawasd

1990-09-01

The performances of some proposed sequential constant-false-alarm-rate (CFAR) detectors are evaluated. The observations are passed through a dead-zone limiter, the output of which is -1, 0, or +1, depending on whether the input is less than -c, between -c and c, or greater than c, where c is a constant. The test statistic is the sum of the outputs. The test is performed on a reduced set of data (those with absolute value larger than c), with the test statistic being the sum of the signs of the reduced set of data. Both constant and linear boundaries are considered. Numerical results show a significant reduction of the average number of observations needed to achieve the same false alarm and detection probabilities as a fixed-sample-size CFAR detector using the same kind of test statistic.

[Comparative study of the repair of full thickness tear of the supraspinatus by means of "single row" or "suture bridge" techniques].

PubMed

Arroyo-Hernández, M; Mellado-Romero, M A; Páramo-Díaz, P; Martín-López, C M; Cano-Egea, J M; Vilá Y Rico, J

2015-01-01

The purpose of this study is to analyze if there is any difference between the arthroscopic reparation of full-thickness supraspinatus tears with simple row technique versus suture bridge technique. We accomplished a retrospective study of 123 patients with full-thickness supraspinatus tears between January 2009 and January 2013 in our hospital. There were 60 simple row reparations, and 63 suture bridge ones. The mean age in the simple row group was 62.9, and in the suture bridge group was 63.3 years old. There were more women than men in both groups (67%). All patients were studied using the Constant test. The mean Constant test in the suture bridge group was 76.7, and in the simple row group was 72.4. We have also accomplished a statistical analysis of each Constant item. Strength was higher in the suture bridge group, with a significant statistical difference (p 0.04). The range of movement was also greater in the suture bridge group, but was not statistically significant. Suture bridge technique has better clinical results than single row reparations, but the difference is not statistically significant (p = 0.298).

The Harm Done to Reproducibility by the Culture of Null Hypothesis Significance Testing.

PubMed

Lash, Timothy L

2017-09-15

In the last few years, stakeholders in the scientific community have raised alarms about a perceived lack of reproducibility of scientific results. In reaction, guidelines for journals have been promulgated and grant applicants have been asked to address the rigor and reproducibility of their proposed projects. Neither solution addresses a primary culprit, which is the culture of null hypothesis significance testing that dominates statistical analysis and inference. In an innovative research enterprise, selection of results for further evaluation based on null hypothesis significance testing is doomed to yield a low proportion of reproducible results and a high proportion of effects that are initially overestimated. In addition, the culture of null hypothesis significance testing discourages quantitative adjustments to account for systematic errors and quantitative incorporation of prior information. These strategies would otherwise improve reproducibility and have not been previously proposed in the widely cited literature on this topic. Without discarding the culture of null hypothesis significance testing and implementing these alternative methods for statistical analysis and inference, all other strategies for improving reproducibility will yield marginal gains at best. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Differences between Lab Completion and Non-Completion on Student Performance in an Online Undergraduate Environmental Science Program

NASA Astrophysics Data System (ADS)

Corsi, Gianluca

2011-12-01

Web-based technology has revolutionized the way education is delivered. Although the advantages of online learning appeal to large numbers of students, some concerns arise. One major concern in online science education is the value that participation in labs has on student performance. The purpose of this study was to assess the relationships between lab completion and student academic success as measured by test grades, scientific self-confidence, scientific skills, and concept mastery. A random sample of 114 volunteer undergraduate students, from an online Environmental Science program at the American Public University System, was tested. The study followed a quantitative, non-experimental research design. Paired sample t-tests were used for statistical comparison between pre-lab and post-lab test grades, two scientific skills quizzes, and two scientific self-confidence surveys administered at the beginning and at the end of the course. The results of the paired sample t-tests revealed statistically significant improvements on all post-lab test scores: Air Pollution lab, t(112) = 6.759, p < .001; Home Chemicals lab t(114) = 8.585, p < .001; Water Use lab, t(116) = 6.657, p < .001; Trees and Carbon lab, t(113) = 9.921, p < .001; Stratospheric Ozone lab, t(112) =12.974, p < .001; Renewable Energy lab, t(115) = 7.369, p < .001. The end of the course Scientific Skills quiz revealed statistically significant improvements, t(112) = 8.221, p < .001. The results of the two surveys showed a statistically significant improvement on student Scientific Self-Confidence because of lab completion, t(114) = 3.015, p < .05. Because age and gender were available, regression models were developed. The results indicated weak multiple correlation coefficients and were not statistically significant at alpha = .05. Evidence suggests that labs play a positive role in a student's academic success. It is recommended that lab experiences be included in all online Environmental Science programs, with emphasis on open-ended inquiries, and adoption of online tools to enhance hands-on experiences, such as virtual reality platforms and digital animations. Future research is encouraged to investigate possible correlations between socio-demographic attributes and academic success of students enrolled in online science programs in reference to lab completion.

Clinical relevance vs. statistical significance: Using neck outcomes in patients with temporomandibular disorders as an example.

PubMed

Armijo-Olivo, Susan; Warren, Sharon; Fuentes, Jorge; Magee, David J

2011-12-01

Statistical significance has been used extensively to evaluate the results of research studies. Nevertheless, it offers only limited information to clinicians. The assessment of clinical relevance can facilitate the interpretation of the research results into clinical practice. The objective of this study was to explore different methods to evaluate the clinical relevance of the results using a cross-sectional study as an example comparing different neck outcomes between subjects with temporomandibular disorders and healthy controls. Subjects were compared for head and cervical posture, maximal cervical muscle strength, endurance of the cervical flexor and extensor muscles, and electromyographic activity of the cervical flexor muscles during the CranioCervical Flexion Test (CCFT). The evaluation of clinical relevance of the results was performed based on the effect size (ES), minimal important difference (MID), and clinical judgement. The results of this study show that it is possible to have statistical significance without having clinical relevance, to have both statistical significance and clinical relevance, to have clinical relevance without having statistical significance, or to have neither statistical significance nor clinical relevance. The evaluation of clinical relevance in clinical research is crucial to simplify the transfer of knowledge from research into practice. Clinical researchers should present the clinical relevance of their results. Copyright © 2011 Elsevier Ltd. All rights reserved.

Evaluation of dredged material proposed for ocean disposal from Hackensack River Project Area, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gruendell, B.D.; Barrows, E.S.; Borde, A.B.

1997-01-01

The objective of the bioassay reevaluation of the Hackensack River Federal Project was to reperform toxicity testing on proposed dredged material with current ammonia reduction protocols. Hackensack River was one of four waterways sampled and evaluated for dredging and disposal in April 1993. Sediment samples were re-collected from the Hackensack River Project area in August 1995. Tests and analyses were conducted according to the manual developed by the USACE and the U.S. Environmental Protection Agency (EPA), Evaluation of Dredged Material Proposed for Ocean Disposal (Testing Manual), commonly referred to as the {open_quotes}Green Book,{close_quotes} and the regional manual developed by themore » USACE-NYD and EPA Region II, Guidance for Performing Tests on Dredged Material to be Disposed of in Ocean Waters. The reevaluation of proposed dredged material from the Hackensack River project area consisted of benthic acute toxicity tests. Thirty-three individual sediment core samples were collected from the Hackensack River project area. Three composite sediments, representing each reach of the area proposed for dredging, were used in benthic acute toxicity testing. Benthic acute toxicity tests were performed with the amphipod Ampelisca abdita and the mysid Mysidopsis bahia. The amphipod and mysid benthic toxicity test procedures followed EPA guidance for reduction of total ammonia concentrations in test systems prior to test initiation. Statistically significant acute toxicity was found in all three Hackensack River composites in the static renewal tests with A. abdita, but not in the static tests with M. bahia. Statistically significant acute toxicity and a greater than 20% increase in mortality over the reference sediment was found in the static renewal tests with A. abdita. Statistically significant mortality 10% over reference sediment was observed in the M. bahia static tests. 5 refs., 2 figs., 2 tabs.« less

Evaluation of dredged material proposed for ocean disposal from Arthur Kill Project Area, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gruendell, B.D.; Barrows, E.S.; Borde, A.B.

1997-01-01

The objective of the bioassay reevaluation of Arthur Kill Federal Project was to reperform toxicity testing on proposed dredged material following current ammonia reduction protocols. Arthur Kill was one of four waterways sampled and evaluated for dredging and disposal in April 1993. Sediment samples were recollected from the Arthur Kill Project areas in August 1995. Tests and analyses were conducted according to the manual developed by the USACE and the U.S. Environmental Protection Agency (EPA), Evaluation of Dredged Material Proposed for Ocean Disposal (Testing Manual), commonly referred to as the {open_quotes}Green Book,{close_quotes} and the regional manual developed by the USACE-NYDmore » and EPA Region II, Guidance for Performing Tests on Dredged Material to be Disposed of in Ocean Waters. The reevaluation of proposed dredged material from the Arthur Kill project areas consisted of benthic acute toxicity tests. Thirty-three individual sediment core samples were collected from the Arthur Kill project area. Three composite sediments, representing each reach of the area proposed for dredging, was used in benthic acute toxicity testing. Benthic acute toxicity tests were performed with the amphipod Ampelisca abdita and the mysid Mysidopsis bahia. The amphipod and mysid benthic toxicity test procedures followed EPA guidance for reduction of total ammonia concentrations in test systems prior to test initiation. Statistically significant acute toxicity was found in all Arthur Kill composites in the static renewal tests with A. abdita, but not in the static tests with M. bahia. Statistically significant acute toxicity and a greater than 20% increase in mortality over the reference sediment was found in the static renewal tests with A. abdita. M. bahia did not show statistically significant acute toxicity or a greater than 10% increase in mortality over reference sediment in static tests. 5 refs., 2 figs., 2 tabs.« less

Plant selection for ethnobotanical uses on the Amalfi Coast (Southern Italy).

PubMed

Savo, V; Joy, R; Caneva, G; McClatchey, W C

2015-07-15

Many ethnobotanical studies have investigated selection criteria for medicinal and non-medicinal plants. In this paper we test several statistical methods using different ethnobotanical datasets in order to 1) define to which extent the nature of the datasets can affect the interpretation of results; 2) determine if the selection for different plant uses is based on phylogeny, or other selection criteria. We considered three different ethnobotanical datasets: two datasets of medicinal plants and a dataset of non-medicinal plants (handicraft production, domestic and agro-pastoral practices) and two floras of the Amalfi Coast. We performed residual analysis from linear regression, the binomial test and the Bayesian approach for calculating under-used and over-used plant families within ethnobotanical datasets. Percentages of agreement were calculated to compare the results of the analyses. We also analyzed the relationship between plant selection and phylogeny, chorology, life form and habitat using the chi-square test. Pearson's residuals for each of the significant chi-square analyses were examined for investigating alternative hypotheses of plant selection criteria. The three statistical analysis methods differed within the same dataset, and between different datasets and floras, but with some similarities. In the two medicinal datasets, only Lamiaceae was identified in both floras as an over-used family by all three statistical methods. All statistical methods in one flora agreed that Malvaceae was over-used and Poaceae under-used, but this was not found to be consistent with results of the second flora in which one statistical result was non-significant. All other families had some discrepancy in significance across methods, or floras. Significant over- or under-use was observed in only a minority of cases. The chi-square analyses were significant for phylogeny, life form and habitat. Pearson's residuals indicated a non-random selection of woody species for non-medicinal uses and an under-use of plants of temperate forests for medicinal uses. Our study showed that selection criteria for plant uses (including medicinal) are not always based on phylogeny. The comparison of different statistical methods (regression, binomial and Bayesian) under different conditions led to the conclusion that the most conservative results are obtained using regression analysis.

Role of the fibula in the stability of diaphyseal tibial fractures fixed by intramedullary nailing.

PubMed

Galbraith, John G; Daly, Charles J; Harty, James A; Dailey, Hannah L

2016-10-01

For tibial fractures, the decision to fix a concomitant fibular fracture is undertaken on a case-by-case basis. To aid in this clinical decision-making process, we investigated whether loss of integrity of the fibula significantly destabilises midshaft tibial fractures, whether fixation of the fibula restores stability to the tibia, and whether removal of the fibula and interosseous membrane for expediency in biomechanical testing significantly influences tibial interfragmentary mechanics. Tibia/fibula pairs were harvested from six cadaveric donors with the interosseous membrane intact. A tibial osteotomy fracture was fixed by reamed intramedullary (IM) nailing. Axial, torsion, bending, and shear tests were completed for four models of fibular involvement: intact fibula, osteotomy fracture, fibular plating, and resected fibula and interosseous membrane. Overall construct stiffness decreased slightly with fibular osteotomy compared to intact bone, but this change was not statistically significant. Under low loads, the influence of the fibula on construct stability was only statistically significant in torsion (large effect size). Fibular plating stiffened the construct slightly, but this change was not statistically significant compared to the fibular osteotomy case. Complete resection of the fibula and interosseous membrane significantly decreased construct torsional stiffness only (large effect size). These results suggest that fixation of the fibula may not contribute significantly to the stability of diaphyseal tibial fractures and should not be undertaken unless otherwise clinically indicated. For testing purposes, load-sharing through the interosseous membrane contributes significantly to overall construct mechanics, especially in torsion, and we recommend preservation of these structures when possible. Copyright © 2016 Elsevier Ltd. All rights reserved.

Serum adipokines and HIV viral replication in patients undergoing antiretroviral therapy

PubMed Central

Aramă, Victoria; Tilişcan, Cătălin; Ion, Daniela Adriana; Mihăilescu, Raluca; Munteanu, Daniela; Streinu-Cercel, Anca; Tudor, Ana Maria; Hristea, Adriana; Leoveanu, Viorica; Olaru, Ioana; Aramă, Ştefan Sorin

2012-01-01

Introduction Several studies have reported that cytokines secreted by adipose tissue (adipokines) may be linked to HIV replication. The aim of the study was to evaluate the relationship between HIV replication and serum levels of adipokines, in a Caucasian HIV-infected population of men and women undergoing complex antiretroviral therapy. Methods A cross-sectional study was conducted in an unselected sample of 77 HIV-1-positive patients. Serum adipokines levels were measured including circulating adiponectin, leptin, resistin, tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6). Patients were divided into two groups: Group 1 - with undetectable viral load and Group 2 - with persistent HIV viral replication. Differences between groups ? were tested using independent-sample t-test for Gaussian variables and Mann–Whitney–Wilcoxon test for non-parametric variables. Pearson's chi-squared test was used for correlation analysis. Results A total of 77 patients (age range: 17-65, mean: 32.5 years) including 44 men (57.1% men, age range: 17–63 years, mean: 34.1 years) and 33 women (42.9% women age range: 19–65 years, mean: 30.3 years) were included in the study. TNF-alpha had significantly higher serum levels in patients with detectable viral load (16.89 vs. 9.35 pg/mL), (p=0.043), but correlation analysis lacked statistical significance. Adiponectin had median serum levels of 9.22 ìg/mL in Group 1 vs. 16.50 ìg/mL in Group 2 but the results lacked statistical significance (p=0.059). Higher leptin, IL-6 and resistin serum levels were noted in patients with undetectable HIV viral load, without statistical significance. Conclusions The present study reported higher TNF-alpha serum levels in patients with persistent HIV viral load. We found no statistically significant correlations between adiponectin, leptin, resistin and IL-6 and HIV viral load in our Caucasian HIV-positive study population, undergoing antiretroviral therapy. PMID:24432258

Relative strength of tailor's bunion osteotomies and fixation techniques.

PubMed

Haddon, Todd B; LaPointe, Stephan J

2013-01-01

A paucity of data is available on the mechanical strength of fifth metatarsal osteotomies. The present study was designed to provide that information. Five osteotomies were mechanically tested to failure using a materials testing machine and compared with an intact fifth metatarsal using a hollow saw bone model with a sample size of 10 for each construct. The osteotomies tested were the distal reverse chevron fixated with a Kirschner wire, the long plantar reverse chevron osteotomy fixated with 2 screws, a mid-diaphyseal sagittal plane osteotomy fixated with 2 screws, the mid-diaphyseal sagittal plane osteotomy fixated with 2 screws, and an additional cerclage wire and a transverse closing wedge osteotomy fixated with a box wire technique. Analysis of variance was performed, resulting in a statistically significant difference among the data at p <.0001. The Tukey-Kramer honestly significant difference with least significant differences was performed post hoc to separate out the pairs at a minimum α of 0.05. The chevron was statistically the strongest construct at 130 N, followed by the long plantar osteotomy at 78 N. The chevron compared well with the control at 114 N, and they both fractured at the proximal model to fixture interface. The other osteotomies were statistically and significantly weaker than both the chevron and the long plantar constructs, with no statistically significant difference among them at 36, 39, and 48 N. In conclusion, the chevron osteotomy was superior in strength to the sagittal and transverse plane osteotomies and similar in strength and failure to the intact model. Copyright © 2013 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Idiopathic normal pressure hydrocephalus, quantitative EEG findings, and the cerebrospinal fluid tap test: a pilot study.

PubMed

Seo, Jong-Geun; Kang, Kyunghun; Jung, Ji-Young; Park, Sung-Pa; Lee, Maan-Gee; Lee, Ho-Won

2014-12-01

In this pilot study, we analyzed relationships between quantitative EEG measurements and clinical parameters in idiopathic normal pressure hydrocephalus patients, along with differences in these quantitative EEG markers between cerebrospinal fluid tap test responders and nonresponders. Twenty-six idiopathic normal pressure hydrocephalus patients (9 cerebrospinal fluid tap test responders and 17 cerebrospinal fluid tap test nonresponders) constituted the final group for analysis. The resting EEG was recorded and relative powers were computed for seven frequency bands. Cerebrospinal fluid tap test nonresponders, when compared with responders, showed a statistically significant increase in alpha2 band power at the right frontal and centrotemporal regions. Higher delta2 band powers in the frontal, central, parietal, and occipital regions and lower alpha1 band powers in the right temporal region significantly correlated with poorer cognitive performance. Higher theta1 band powers in the left parietal and occipital regions significantly correlated with gait dysfunction. And higher delta1 band powers in the right frontal regions significantly correlated with urinary disturbance. Our findings may encourage further research using quantitative EEG in patients with ventriculomegaly as a potential electrophysiological marker for predicting cerebrospinal fluid tap test responders. This study additionally suggests that the delta, theta, and alpha bands are statistically correlated with the severity of symptoms in idiopathic normal pressure hydrocephalus patients.

Optimizing α for better statistical decisions: a case study involving the pace-of-life syndrome hypothesis: optimal α levels set to minimize Type I and II errors frequently result in different conclusions from those using α = 0.05.

PubMed

Mudge, Joseph F; Penny, Faith M; Houlahan, Jeff E

2012-12-01

Setting optimal significance levels that minimize Type I and Type II errors allows for more transparent and well-considered statistical decision making compared to the traditional α = 0.05 significance level. We use the optimal α approach to re-assess conclusions reached by three recently published tests of the pace-of-life syndrome hypothesis, which attempts to unify occurrences of different physiological, behavioral, and life history characteristics under one theory, over different scales of biological organization. While some of the conclusions reached using optimal α were consistent to those previously reported using the traditional α = 0.05 threshold, opposing conclusions were also frequently reached. The optimal α approach reduced probabilities of Type I and Type II errors, and ensured statistical significance was associated with biological relevance. Biologists should seriously consider their choice of α when conducting null hypothesis significance tests, as there are serious disadvantages with consistent reliance on the traditional but arbitrary α = 0.05 significance level. Copyright © 2012 WILEY Periodicals, Inc.

Confidence intervals for effect sizes: compliance and clinical significance in the Journal of Consulting and clinical Psychology.

PubMed

Odgaard, Eric C; Fowler, Robert L

2010-06-01

In 2005, the Journal of Consulting and Clinical Psychology (JCCP) became the first American Psychological Association (APA) journal to require statistical measures of clinical significance, plus effect sizes (ESs) and associated confidence intervals (CIs), for primary outcomes (La Greca, 2005). As this represents the single largest editorial effort to improve statistical reporting practices in any APA journal in at least a decade, in this article we investigate the efficacy of that change. All intervention studies published in JCCP in 2003, 2004, 2007, and 2008 were reviewed. Each article was coded for method of clinical significance, type of ES, and type of associated CI, broken down by statistical test (F, t, chi-square, r/R(2), and multivariate modeling). By 2008, clinical significance compliance was 75% (up from 31%), with 94% of studies reporting some measure of ES (reporting improved for individual statistical tests ranging from eta(2) = .05 to .17, with reasonable CIs). Reporting of CIs for ESs also improved, although only to 40%. Also, the vast majority of reported CIs used approximations, which become progressively less accurate for smaller sample sizes and larger ESs (cf. Algina & Kessleman, 2003). Changes are near asymptote for ESs and clinical significance, but CIs lag behind. As CIs for ESs are required for primary outcomes, we show how to compute CIs for the vast majority of ESs reported in JCCP, with an example of how to use CIs for ESs as a method to assess clinical significance.

Invited Commentary: Can Issues With Reproducibility in Science Be Blamed on Hypothesis Testing?

PubMed Central

Weinberg, Clarice R.

2017-01-01

Abstract In the accompanying article (Am J Epidemiol. 2017;186(6):646–647), Dr. Timothy Lash makes a forceful case that the problems with reproducibility in science stem from our “culture” of null hypothesis significance testing. He notes that when attention is selectively given to statistically significant findings, the estimated effects will be systematically biased away from the null. Here I revisit the recent history of genetic epidemiology and argue for retaining statistical testing as an important part of the tool kit. Particularly when many factors are considered in an agnostic way, in what Lash calls “innovative” research, investigators need a selection strategy to identify which findings are most likely to be genuine, and hence worthy of further study. PMID:28938713

Low power and type II errors in recent ophthalmology research.

PubMed

Khan, Zainab; Milko, Jordan; Iqbal, Munir; Masri, Moness; Almeida, David R P

2016-10-01

To investigate the power of unpaired t tests in prospective, randomized controlled trials when these tests failed to detect a statistically significant difference and to determine the frequency of type II errors. Systematic review and meta-analysis. We examined all prospective, randomized controlled trials published between 2010 and 2012 in 4 major ophthalmology journals (Archives of Ophthalmology, British Journal of Ophthalmology, Ophthalmology, and American Journal of Ophthalmology). Studies that used unpaired t tests were included. Power was calculated using the number of subjects in each group, standard deviations, and α = 0.05. The difference between control and experimental means was set to be (1) 20% and (2) 50% of the absolute value of the control's initial conditions. Power and Precision version 4.0 software was used to carry out calculations. Finally, the proportion of articles with type II errors was calculated. β = 0.3 was set as the largest acceptable value for the probability of type II errors. In total, 280 articles were screened. Final analysis included 50 prospective, randomized controlled trials using unpaired t tests. The median power of tests to detect a 50% difference between means was 0.9 and was the same for all 4 journals regardless of the statistical significance of the test. The median power of tests to detect a 20% difference between means ranged from 0.26 to 0.9 for the 4 journals. The median power of these tests to detect a 50% and 20% difference between means was 0.9 and 0.5 for tests that did not achieve statistical significance. A total of 14% and 57% of articles with negative unpaired t tests contained results with β > 0.3 when power was calculated for differences between means of 50% and 20%, respectively. A large portion of studies demonstrate high probabilities of type II errors when detecting small differences between means. The power to detect small difference between means varies across journals. It is, therefore, worthwhile for authors to mention the minimum clinically important difference for individual studies. Journals can consider publishing statistical guidelines for authors to use. Day-to-day clinical decisions rely heavily on the evidence base formed by the plethora of studies available to clinicians. Prospective, randomized controlled clinical trials are highly regarded as a robust study and are used to make important clinical decisions that directly affect patient care. The quality of study designs and statistical methods in major clinical journals is improving overtime, 1 and researchers and journals are being more attentive to statistical methodologies incorporated by studies. The results of well-designed ophthalmic studies with robust methodologies, therefore, have the ability to modify the ways in which diseases are managed. Copyright © 2016 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Comparative Evaluation of Microleakage Between Nano-Ionomer, Giomer and Resin Modified Glass Ionomer Cement in Class V Cavities- CLSM Study.

PubMed

Bollu, Indira Priyadarshini; Hari, Archana; Thumu, Jayaprakash; Velagula, Lakshmi Deepa; Bolla, Nagesh; Varri, Sujana; Kasaraneni, Srikanth; Nalli, Siva Venkata Malathi

2016-05-01

Marginal integrity of adhesive restorative materials provides better sealing ability for enamel and dentin and plays an important role in success of restoration in Class V cavities. Restorative material with good marginal adaptation improves the longevity of restorations. Aim of this study was to evaluate microleakage in Class V cavities which were restored with Resin Modified Glass Ionomer Cement (RMGIC), Giomer and Nano-Ionomer. This in-vitro study was performed on 60 human maxillary and mandibular premolars which were extracted for orthodontic reasons. A standard wedge shaped defect was prepared on the buccal surfaces of teeth with the gingival margin placed near Cemento Enamel Junction (CEJ). Teeth were divided into three groups of 20 each and restored with RMGIC, Giomer and Nano-Ionomer and were subjected to thermocycling. Teeth were then immersed in 0.5% Rhodamine B dye for 48 hours. They were sectioned longitudinally from the middle of cavity into mesial and distal parts. The sections were observed under Confocal Laser Scanning Microscope (CLSM) to evaluate microleakage. Depth of dye penetration was measured in millimeters. The data was analysed using the Kruskal Wallis test. Pair wise comparison was done with Mann Whitney U Test. A p-value<0.05 is taken as statistically significant. Nano-Ionomer showed less microleakage which was statistically significant when compared to Giomer (p=0.0050). Statistically no significant difference was found between Nano Ionomer and RMGIC (p=0.3550). There was statistically significant difference between RMGIC and Giomer (p=0.0450). Nano-Ionomer and RMGIC showed significantly less leakage and better adaptation than Giomer and there was no statistically significant difference between Nano-Ionomer and RMGIC.

Evaluation of salivary fluoride retention from a new high fluoride mouthrinse.

PubMed

Mason, Stephen C; Shirodaria, Soha; Sufi, Farzana; Rees, Gareth D; Birkhed, Dowen

2010-11-01

To evaluate salivary fluoride retention from a new high fluoride daily use mouthrinse over a 120 min period. Sixteen subjects completed a randomised single-blind, four-treatment cross-over trial. Sensodyne® Pronamel® mouthrinse (A) contained 450 ppm fluoride; reference products were Colgate® Fluorigard® (B), Listerine® Total Care (C) and Listerine Softmint Sensation (D) containing 225, 100 and 0 ppm fluoride respectively. Salivary fluoride retention was monitored ex vivo after a single supervised use of test product (10 mL, 60 s). Samples were collected at 0, 1, 3, 5, 15, 30, 60 and 120 min post-rinse, generating fluoride clearance curves from which the area under the curve (AUC) was calculated. Differences in salivary fluoride concentrations for each product were analysed using ANCOVA at each time point using a 5% significance level, as well as lnAUC for the periods 0-120, 0-1, 1-15, 15-60 and 60-120 min. Pairwise comparisons between all treatment groups were performed. Salivary fluoride levels for A-C peaked immediately following use. Fluoride levels were statistically significantly higher for A versus B-D (p≤ 0.004), linear dose responses were apparent. AUC(0-120) was statistically significantly greater for A than for B (p = 0.035), C (p< 0.0001) and D (p< 0.0001). Post-hoc comparisons of lnAUC for the remaining time domains showed fluoride retention from A was statistically significantly greater versus B-D (p< 0.0001). Single-use treatment with the new mouthrinse containing 450 ppm fluoride resulted in statistically significantly higher salivary fluoride levels throughout the 120 min test period. Total fluoride retention (AUC(0-120)) was also statistically significantly greater versus comparator rinse treatments. Copyright © 2010 Elsevier Ltd. All rights reserved.

Validation of a modification to Performance-Tested Method 070601: Reveal Listeria Test for detection of Listeria spp. in selected foods and selected environmental samples.

PubMed

Alles, Susan; Peng, Linda X; Mozola, Mark A

2009-01-01

A modification to Performance-Tested Method (PTM) 070601, Reveal Listeria Test (Reveal), is described. The modified method uses a new media formulation, LESS enrichment broth, in single-step enrichment protocols for both foods and environmental sponge and swab samples. Food samples are enriched for 27-30 h at 30 degrees C and environmental samples for 24-48 h at 30 degrees C. Implementation of these abbreviated enrichment procedures allows test results to be obtained on a next-day basis. In testing of 14 food types in internal comparative studies with inoculated samples, there was a statistically significant difference in performance between the Reveal and reference culture [U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA/BAM) or U.S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS)] methods for only a single food in one trial (pasteurized crab meat) at the 27 h enrichment time point, with more positive results obtained with the FDA/BAM reference method. No foods showed statistically significant differences in method performance at the 30 h time point. Independent laboratory testing of 3 foods again produced a statistically significant difference in results for crab meat at the 27 h time point; otherwise results of the Reveal and reference methods were statistically equivalent. Overall, considering both internal and independent laboratory trials, sensitivity of the Reveal method relative to the reference culture procedures in testing of foods was 85.9% at 27 h and 97.1% at 30 h. Results from 5 environmental surfaces inoculated with various strains of Listeria spp. showed that the Reveal method was more productive than the reference USDA-FSIS culture procedure for 3 surfaces (stainless steel, plastic, and cast iron), whereas results were statistically equivalent to the reference method for the other 2 surfaces (ceramic tile and sealed concrete). An independent laboratory trial with ceramic tile inoculated with L. monocytogenes confirmed the effectiveness of the Reveal method at the 24 h time point. Overall, sensitivity of the Reveal method at 24 h relative to that of the USDA-FSIS method was 153%. The Reveal method exhibited extremely high specificity, with only a single false-positive result in all trials combined for overall specificity of 99.5%.

Effects of different centrifugation conditions on clinical chemistry and Immunology test results.

PubMed

Minder, Elisabeth I; Schibli, Adrian; Mahrer, Dagmar; Nesic, Predrag; Plüer, Kathrin

2011-05-10

The effect of centrifugation time of heparinized blood samples on clinical chemistry and immunology results has rarely been studied. WHO guideline proposed a 15 min centrifugation time without citing any scientific publications. The centrifugation time has a considerable impact on the turn-around-time. We investigated 74 parameters in samples from 44 patients on a Roche Cobas 6000 system, to see whether there was a statistical significant difference in the test results among specimens centrifuged at 2180 g for 15 min, at 2180 g for 10 min or at 1870 g for 7 min, respectively. Two tubes with different plasma separators (both Greiner Bio-One) were used for each centrifugation condition. Statistical comparisons were made by Deming fit. Tubes with different separators showed identical results in all parameters. Likewise, excellent correlations were found among tubes to which different centrifugation conditions were applied. Fifty percent of the slopes lay between 0.99 and 1.01. Only 3.6 percent of the statistical tests results fell outside the significance level of p < 0.05, which was less than the expected 5%. This suggests that the outliers are the result of random variation and the large number of statistical tests performed. Further, we found that our data are sufficient not to miss a biased test (beta error) with a probability of 0.10 to 0.05 in most parameters. A centrifugation time of either 7 or 10 min provided identical test results compared to the time of 15 min as proposed by WHO under the conditions used in our study.

Effects of different centrifugation conditions on clinical chemistry and Immunology test results

PubMed Central

2011-01-01

Background The effect of centrifugation time of heparinized blood samples on clinical chemistry and immunology results has rarely been studied. WHO guideline proposed a 15 min centrifugation time without citing any scientific publications. The centrifugation time has a considerable impact on the turn-around-time. Methods We investigated 74 parameters in samples from 44 patients on a Roche Cobas 6000 system, to see whether there was a statistical significant difference in the test results among specimens centrifuged at 2180 g for 15 min, at 2180 g for 10 min or at 1870 g for 7 min, respectively. Two tubes with different plasma separators (both Greiner Bio-One) were used for each centrifugation condition. Statistical comparisons were made by Deming fit. Results Tubes with different separators showed identical results in all parameters. Likewise, excellent correlations were found among tubes to which different centrifugation conditions were applied. Fifty percent of the slopes lay between 0.99 and 1.01. Only 3.6 percent of the statistical tests results fell outside the significance level of p < 0.05, which was less than the expected 5%. This suggests that the outliers are the result of random variation and the large number of statistical tests performed. Further, we found that our data are sufficient not to miss a biased test (beta error) with a probability of 0.10 to 0.05 in most parameters. Conclusion A centrifugation time of either 7 or 10 min provided identical test results compared to the time of 15 min as proposed by WHO under the conditions used in our study. PMID:21569233

First Results from the Light and Spectroscopy Concept Inventory

ERIC Educational Resources Information Center

Bardar, Erin M.

2008-01-01

This article presents results from a two-semester field test of the Light and Spectroscopy Concept Inventory (LSCI). Statistical analysis indicates that the LSCI has the sensitivity to measure statistically significant changes in students' understanding of light-related topics due to instruction in introductory astronomy courses and to distinguish…

Three Strategies for the Critical Use of Statistical Methods in Psychological Research

ERIC Educational Resources Information Center

Campitelli, Guillermo; Macbeth, Guillermo; Ospina, Raydonal; Marmolejo-Ramos, Fernando

2017-01-01

We present three strategies to replace the null hypothesis statistical significance testing approach in psychological research: (1) visual representation of cognitive processes and predictions, (2) visual representation of data distributions and choice of the appropriate distribution for analysis, and (3) model comparison. The three strategies…

Lighting the way: photonics leaders II (PL2) optics and photonics teacher professional development

NASA Astrophysics Data System (ADS)

Gilchrist, Pamela O.; Hilliard-Clark, Joyce; Bowles, Tuere; Carpenter, Eric

2014-07-01

A sample group of nineteen teachers completed the second phase of the Photonics Leaders II Optics and Photonics professional development program. Participants took a basic Physics content knowledge test that was designed by a Professor of Physics. The test was completed before the teachers participated in the program and at the end of the program to gather data for statistical inquiry. Statistical studies on pre-test and post-test data indicated significant gains in physics content knowledge over time, and that instructors teaching at the middle school level or only teaching one subject area scored significantly lower during the pretest. Reports from previous participants are summarized to disseminate the percentage of teachers who have incorporated at least one workshop activity and the kind of activity performed. The concerns and limitations reported by previous participants are reviewed as well.

An Extension of the Chi-Square Procedure for Non-NORMAL Statistics, with Application to Solar Neutrino Data

NASA Astrophysics Data System (ADS)

Sturrock, P. A.

2008-01-01

Using the chi-square statistic, one may conveniently test whether a series of measurements of a variable are consistent with a constant value. However, that test is predicated on the assumption that the appropriate probability distribution function (pdf) is normal in form. This requirement is usually not satisfied by experimental measurements of the solar neutrino flux. This article presents an extension of the chi-square procedure that is valid for any form of the pdf. This procedure is applied to the GALLEX-GNO dataset, and it is shown that the results are in good agreement with the results of Monte Carlo simulations. Whereas application of the standard chi-square test to symmetrized data yields evidence significant at the 1% level for variability of the solar neutrino flux, application of the extended chi-square test to the unsymmetrized data yields only weak evidence (significant at the 4% level) of variability.

EXTENDING MULTIVARIATE DISTANCE MATRIX REGRESSION WITH AN EFFECT SIZE MEASURE AND THE ASYMPTOTIC NULL DISTRIBUTION OF THE TEST STATISTIC

PubMed Central

McArtor, Daniel B.; Lubke, Gitta H.; Bergeman, C. S.

2017-01-01

Person-centered methods are useful for studying individual differences in terms of (dis)similarities between response profiles on multivariate outcomes. Multivariate distance matrix regression (MDMR) tests the significance of associations of response profile (dis)similarities and a set of predictors using permutation tests. This paper extends MDMR by deriving and empirically validating the asymptotic null distribution of its test statistic, and by proposing an effect size for individual outcome variables, which is shown to recover true associations. These extensions alleviate the computational burden of permutation tests currently used in MDMR and render more informative results, thus making MDMR accessible to new research domains. PMID:27738957

Extending multivariate distance matrix regression with an effect size measure and the asymptotic null distribution of the test statistic.

PubMed

McArtor, Daniel B; Lubke, Gitta H; Bergeman, C S

2017-12-01

Person-centered methods are useful for studying individual differences in terms of (dis)similarities between response profiles on multivariate outcomes. Multivariate distance matrix regression (MDMR) tests the significance of associations of response profile (dis)similarities and a set of predictors using permutation tests. This paper extends MDMR by deriving and empirically validating the asymptotic null distribution of its test statistic, and by proposing an effect size for individual outcome variables, which is shown to recover true associations. These extensions alleviate the computational burden of permutation tests currently used in MDMR and render more informative results, thus making MDMR accessible to new research domains.

tscvh R Package: Computational of the two samples test on microarray-sequencing data

NASA Astrophysics Data System (ADS)

Fajriyah, Rohmatul; Rosadi, Dedi

2017-12-01

We present a new R package, a tscvh (two samples cross-variance homogeneity), as we called it. This package is a software of the cross-variance statistical test which has been proposed and introduced by Fajriyah ([3] and [4]), based on the cross-variance concept. The test can be used as an alternative test for the significance difference between two means when sample size is small, the situation which is usually appeared in the bioinformatics research. Based on its statistical distribution, the p-value can be also provided. The package is built under a homogeneity of variance between samples.

A comparison of face to face and group education on informed choice and decisional conflict of pregnant women about screening tests of fetal abnormalities

PubMed Central

Kordi, Masoumeh; Riyazi, Sahar; Lotfalizade, Marziyeh; Shakeri, Mohammad Taghi; Suny, Hoseyn Jafari

2018-01-01

BACKGROUND AND GOAL: Screening of fetal anomalies is assumed as a necessary measurement in antenatal cares. The screening plans aim at empowerment of individuals to make the informed choice. This study was conducted in order to compare the effect of group and face-to-face education and decisional conflicts among the pregnant females regarding screening of fetal abnormalities. METHODS: This study of the clinical trial was carried out on 240 pregnant women at <10-week pregnancy age in health care medical centers in Mashhad city in 2014. The form of individual-midwifery information and informed choice questionnaire and decisional conflict scale were used as tools for data collection. The face-to-face and group education course were held in two weekly sessions for intervention groups during two consecutive weeks, and the usual care was conducted for the control group. The rate of informed choice and decisional conflict was measured in pregnant women before education and also at weeks 20–22 of pregnancy in three groups. The data analysis was executed using SPSS statistical software (version 16), and statistical tests were implemented including Chi-square test, Kruskal–Wallis test, Wilcoxon test, Mann–Whitney U-test, one-way analysis of variance test, and Tukey's range test. The P < 0.05 was considered as a significant. RESULTS: The results showed that there was statically significant difference between three groups in terms of frequency of informed choice in screening of fetal abnormalities (P = 0.001) in such a way that at next step of intervention, 62 participants (77.5%) in face-to-face education group, 64 members (80%) in group education class, and 20 persons (25%) in control group had the informed choice regarding screening tests, but there was no statistically significant difference between two individual and group education classes. Similarly, during the postintervention phase, there was a statistically significant difference in mean score of decisional conflict scale among pregnant women regarding screening tests in three groups (P = 0.001). DISCUSSION AND CONCLUSION: With respect to effectiveness of group and face-to-face education methods in increasing the informed choice and reduced decisional conflict in pregnant women regarding screening tests, each of these education methods may be employed according to the clinical environment conditions and requirement to encourage the women for conducting the screening tests. PMID:29417066

[Evaluation of using statistical methods in selected national medical journals].

PubMed

Sych, Z

1996-01-01

The paper covers the performed evaluation of frequency with which the statistical methods were applied in analyzed works having been published in six selected, national medical journals in the years 1988-1992. For analysis the following journals were chosen, namely: Klinika Oczna, Medycyna Pracy, Pediatria Polska, Polski Tygodnik Lekarski, Roczniki Państwowego Zakładu Higieny, Zdrowie Publiczne. Appropriate number of works up to the average in the remaining medical journals was randomly selected from respective volumes of Pol. Tyg. Lek. The studies did not include works wherein the statistical analysis was not implemented, which referred both to national and international publications. That exemption was also extended to review papers, casuistic ones, reviews of books, handbooks, monographies, reports from scientific congresses, as well as papers on historical topics. The number of works was defined in each volume. Next, analysis was performed to establish the mode of finding out a suitable sample in respective studies, differentiating two categories: random and target selections. Attention was also paid to the presence of control sample in the individual works. In the analysis attention was also focussed on the existence of sample characteristics, setting up three categories: complete, partial and lacking. In evaluating the analyzed works an effort was made to present the results of studies in tables and figures (Tab. 1, 3). Analysis was accomplished with regard to the rate of employing statistical methods in analyzed works in relevant volumes of six selected, national medical journals for the years 1988-1992, simultaneously determining the number of works, in which no statistical methods were used. Concurrently the frequency of applying the individual statistical methods was analyzed in the scrutinized works. Prominence was given to fundamental statistical methods in the field of descriptive statistics (measures of position, measures of dispersion) as well as most important methods of mathematical statistics such as parametric tests of significance, analysis of variance (in single and dual classifications). non-parametric tests of significance, correlation and regression. The works, in which use was made of either multiple correlation or multiple regression or else more complex methods of studying the relationship for two or more numbers of variables, were incorporated into the works whose statistical methods were constituted by correlation and regression as well as other methods, e.g. statistical methods being used in epidemiology (coefficients of incidence and morbidity, standardization of coefficients, survival tables) factor analysis conducted by Jacobi-Hotellng's method, taxonomic methods and others. On the basis of the performed studies it has been established that the frequency of employing statistical methods in the six selected national, medical journals in the years 1988-1992 was 61.1-66.0% of the analyzed works (Tab. 3), and they generally were almost similar to the frequency provided in English language medical journals. On a whole, no significant differences were disclosed in the frequency of applied statistical methods (Tab. 4) as well as in frequency of random tests (Tab. 3) in the analyzed works, appearing in the medical journals in respective years 1988-1992. The most frequently used statistical methods in analyzed works for 1988-1992 were the measures of position 44.2-55.6% and measures of dispersion 32.5-38.5% as well as parametric tests of significance 26.3-33.1% of the works analyzed (Tab. 4). For the purpose of increasing the frequency and reliability of the used statistical methods, the didactics should be widened in the field of biostatistics at medical studies and postgraduation training designed for physicians and scientific-didactic workers.

Aniracetam tested in chronic psychosyndrome after long-term exposure to organic solvents. A randomized, double-blind, placebo-controlled cross-over study with neuropsychological tests.

PubMed

Somnier, F E; Ostergaard, M S; Boysen, G; Bruhn, P; Mikkelsen, B O

1990-01-01

In order to examine if the nootropic drug, aniracetam, was capable of improving cognitive performance, 44 subjects suffering from chronic psychosyndrome after long-term exposure to organic solvents were included in a randomized, double-blind, placebo-controlled, cross-over study. The treatment periods were 3 months with aniracetam 1 g daily and 3 months with placebo. Neuropsychological tests as well as a physical and neurological examination were performed at entry into the study and after each treatment period, together with an evaluation of the subjects' overall condition. Neither the doctors' nor the subjects' own assessment of the overall condition indicated that the trial medication had had any effect. No significant changes in neuropsychological symptoms were observed. A statistically significant difference in favour of antiracetam was found in only 1 of the 19 neuropsychological test measures, namely a test for constructional ability. However, in another test on visuo-spatial function, a statistically significant result was found in favour of placebo. Thus, aniracetam was found to be ineffective in the treatment of subjects suffering from chronic psychosyndrome after long-term exposure to organic solvents.

Test anxiety and academic performance in chiropractic students.

PubMed

Zhang, Niu; Henderson, Charles N R

2014-01-01

Objective : We assessed the level of students' test anxiety, and the relationship between test anxiety and academic performance. Methods : We recruited 166 third-quarter students. The Test Anxiety Inventory (TAI) was administered to all participants. Total scores from written examinations and objective structured clinical examinations (OSCEs) were used as response variables. Results : Multiple regression analysis shows that there was a modest, but statistically significant negative correlation between TAI scores and written exam scores, but not OSCE scores. Worry and emotionality were the best predictive models for written exam scores. Mean total anxiety and emotionality scores for females were significantly higher than those for males, but not worry scores. Conclusion : Moderate-to-high test anxiety was observed in 85% of the chiropractic students examined. However, total test anxiety, as measured by the TAI score, was a very weak predictive model for written exam performance. Multiple regression analysis demonstrated that replacing total anxiety (TAI) with worry and emotionality (TAI subscales) produces a much more effective predictive model of written exam performance. Sex, age, highest current academic degree, and ethnicity contributed little additional predictive power in either regression model. Moreover, TAI scores were not found to be statistically significant predictors of physical exam skill performance, as measured by OSCEs.

STATISTICAL ANALYSIS OF SNAP 10A THERMOELECTRIC CONVERTER ELEMENT PROCESS DEVELOPMENT VARIABLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fitch, S.H.; Morris, J.W.

1962-12-15

Statistical analysis, primarily analysis of variance, was applied to evaluate several factors involved in the development of suitable fabrication and processing techniques for the production of lead telluride thermoelectric elements for the SNAP 10A energy conversion system. The analysis methods are described as to their application for determining the effects of various processing steps, estabIishing the value of individual operations, and evaluating the significance of test results. The elimination of unnecessary or detrimental processing steps was accomplished and the number of required tests was substantially reduced by application of these statistical methods to the SNAP 10A production development effort. (auth)

Abstracts of ARI Research Publications, FY 1978

DTIC Science & Technology

1980-09-01

initial item pool, 49 items were identified as having signifi- cant item-to-total-score correlations and were statistically determined to address a...failing. Differences among the three groups on main gun performance measures and the previous experience of gun- ners were not statistically significant...forms of the noncognitive cod- ing speed test; and (d) a second field administration to derive norms and other statistical characteristics of the new

'Chain pooling' model selection as developed for the statistical analysis of a rotor burst protection experiment

NASA Technical Reports Server (NTRS)

Holms, A. G.

1977-01-01

A statistical decision procedure called chain pooling had been developed for model selection in fitting the results of a two-level fixed-effects full or fractional factorial experiment not having replication. The basic strategy included the use of one nominal level of significance for a preliminary test and a second nominal level of significance for the final test. The subject has been reexamined from the point of view of using as many as three successive statistical model deletion procedures in fitting the results of a single experiment. The investigation consisted of random number studies intended to simulate the results of a proposed aircraft turbine-engine rotor-burst-protection experiment. As a conservative approach, population model coefficients were chosen to represent a saturated 2 to the 4th power experiment with a distribution of parameter values unfavorable to the decision procedures. Three model selection strategies were developed.

The effect of digital rectal exam on the 4Kscore for aggressive prostate cancer.

PubMed

Maccini, Michael A; Westfall, Nicholas J; Van Bokhoven, Adrie; Lucia, Marshall Scott; Poage, Wendy; Maroni, Paul D; Wilson, Shandra S; Glodé, Leonard Michael; Arangua, Paul; Newmark, Jay; Steiner, Mitchell; Werahera, Priya N; Crawford, Elward David

2018-05-01

The 4Kscore is a new commercially available blood-based diagnostic test which predicts risk for aggressive, clinically significant prostate cancer on prostate biopsy. The 4Kscore is currently restricted to patients who have not had a digital rectal exam (DRE) in the previous 96 h, owing to prior mixed data suggesting that prostate specific antigen (PSA) isoforms may increase by a statistically significant-if not necessarily clinically significant-amount shortly after DRE. Our primary objective was to determine if 4Kscore test results are affected by a preceding DRE. Participants at a Prostate Cancer Awareness Week screening event sponsored by the Prostate Conditions Education Council filled out clinical history questionnaires and had blood samples for 4Kscore testing drawn prior to DRE, then 15-45 min following DRE. Patients with prior cancer diagnosis, 5-alpha reductase inhibitor medication use, or lower urinary tract procedures in the prior 6 months were excluded, resulting in a population of 162 participants for analysis. Values were then compared to determine if there was a significant difference in 4Kscore following DRE. A statistically significant increase was seen in levels of 3 kallikreins measured (total PSA, free PSA, and intact PSA; median <0.03 ng/mL for all). This resulted in a small but statistically significant decrease in post-DRE 4Kscore (median absolute score decrease 0.43%). Using a 4Kscore cutoff of 7.5% resulted in reclassification of 10 patients (6.2%), nine of whom were "downgraded" from above the cutoff to below. If the blood draw for the 4 K score is performed after a screening DRE, there is a statistically significant difference in the 4 K score results, but in the vast majority of cases it would not affect clinical decision making. © 2018 Wiley Periodicals, Inc.

Effect of non-normality on test statistics for one-way independent groups designs.

PubMed

Cribbie, Robert A; Fiksenbaum, Lisa; Keselman, H J; Wilcox, Rand R

2012-02-01

The data obtained from one-way independent groups designs is typically non-normal in form and rarely equally variable across treatment populations (i.e., population variances are heterogeneous). Consequently, the classical test statistic that is used to assess statistical significance (i.e., the analysis of variance F test) typically provides invalid results (e.g., too many Type I errors, reduced power). For this reason, there has been considerable interest in finding a test statistic that is appropriate under conditions of non-normality and variance heterogeneity. Previously recommended procedures for analysing such data include the James test, the Welch test applied either to the usual least squares estimators of central tendency and variability, or the Welch test with robust estimators (i.e., trimmed means and Winsorized variances). A new statistic proposed by Krishnamoorthy, Lu, and Mathew, intended to deal with heterogeneous variances, though not non-normality, uses a parametric bootstrap procedure. In their investigation of the parametric bootstrap test, the authors examined its operating characteristics under limited conditions and did not compare it to the Welch test based on robust estimators. Thus, we investigated how the parametric bootstrap procedure and a modified parametric bootstrap procedure based on trimmed means perform relative to previously recommended procedures when data are non-normal and heterogeneous. The results indicated that the tests based on trimmed means offer the best Type I error control and power when variances are unequal and at least some of the distribution shapes are non-normal. © 2011 The British Psychological Society.

Effect of Internet-Based Cognitive Apprenticeship Model (i-CAM) on Statistics Learning among Postgraduate Students

PubMed Central

Saadati, Farzaneh; Ahmad Tarmizi, Rohani

2015-01-01

Because students’ ability to use statistics, which is mathematical in nature, is one of the concerns of educators, embedding within an e-learning system the pedagogical characteristics of learning is ‘value added’ because it facilitates the conventional method of learning mathematics. Many researchers emphasize the effectiveness of cognitive apprenticeship in learning and problem solving in the workplace. In a cognitive apprenticeship learning model, skills are learned within a community of practitioners through observation of modelling and then practice plus coaching. This study utilized an internet-based Cognitive Apprenticeship Model (i-CAM) in three phases and evaluated its effectiveness for improving statistics problem-solving performance among postgraduate students. The results showed that, when compared to the conventional mathematics learning model, the i-CAM could significantly promote students’ problem-solving performance at the end of each phase. In addition, the combination of the differences in students' test scores were considered to be statistically significant after controlling for the pre-test scores. The findings conveyed in this paper confirmed the considerable value of i-CAM in the improvement of statistics learning for non-specialized postgraduate students. PMID:26132553

Factors affecting the distribution and prevalence of oral mucosal lesions in complete denture wearers.

PubMed

Mandali, Gamze; Sener, Işıl Damla; Turker, Sebnem Begum; Ulgen, Hasan

2011-06-01

To determine the frequency of the oral lesions related to gender, age, the length of time of denture usage, education level and economic status. The 153 patients with old complete dentures (CD) were asked to participate in the investigation. The subjects (76 male and 77 female) were 37-85 years of age with a mean age of 61.8 ± 9.8 years. Education, economic status and age factors were estimated in subgroups. The data obtained were evaluated by one-way anova, Mann-Whitney U-test, Kruskal-Wallis test, Student's t-test and chi-squared test. The level of statistical significance was set at p<0.05. The patients who had denture stomatitis and traumatic ulcers were statistically significantly older than the ones who did not have these lesions (p<0.05). Based on the length of denture usage, patients who had a flabby ridge, fibrous inflammatory hyperplasia, traumatic ulcers (p<0.01) and denture stomatitis (p<0.05) were using their dentures statistically significantly longer than the ones who had healthy tissues. The CD wearers should be advised to visit their dentist regularly to prevent oral mucosal lesions due to the changing supporting tissues during the length of denture usage and to improve their quality of life. © 2010 The Gerodontology Society and John Wiley & Sons A/S.

Evaluation of setting time and flow properties of self-synthesize alginate impressions

NASA Astrophysics Data System (ADS)

Halim, Calista; Cahyanto, Arief; Sriwidodo, Harsatiningsih, Zulia

2018-02-01

Alginate is an elastic hydrocolloid dental impression materials to obtain negative reproduction of oral mucosa such as to record soft-tissue and occlusal relationships. The aim of the present study was to synthesize alginate and to determine the setting time and flow properties. There were five groups of alginate consisted of fifty samples self-synthesize alginate and commercial alginate impression product. Fifty samples were divided according to two tests, each twenty-five samples for setting time and flow test. Setting time test was recorded in the s unit, meanwhile, flow test was recorded in the mm2 unit. The fastest setting time result was in the group three (148.8 s) and the latest was group fours). The highest flow test result was in the group three (69.70 mm2) and the lowest was group one (58.34 mm2). Results were analyzed statistically by one way ANOVA (α= 0.05), showed that there was a statistical significance of setting time while no statistical significance of flow properties between self-synthesize alginate and alginate impression product. In conclusion, the alginate impression was successfully self-synthesized and variation composition gives influence toward setting time and flow properties. The most resemble setting time of control group is group three. The most resemble flow of control group is group four.

Fracture resistance of aluminium oxide and lithium disilicate-based crowns using different luting cements: an in vitro study.

PubMed

Al-Wahadni, Ahed M; Hussey, David L; Grey, Nicholas; Hatamleh, Muhanad M

2009-03-01

The aim of this study was to investigate the fracture resistance of two types of ceramic crowns cemented with two different cements. Forty premolar crowns were fabricated using lithium-disilicate (IPS Empress-2) and glass-infiltrated aluminium-oxide (In-Ceram) ceramic systems. The crowns were divided into four groups (n=10) with Group 1 (IPS Empress-2) and Group 2 (In-Ceram) cemented with glass ionomer cement. Group 3 (IPS Empress-2) and Group 4 (In-Ceram) were cemented with resin cement. Crowns were tested in a universal testing machine at a compressive-load speed of 10 mm/min. Fracture modes were grouped into five categories. One way analysis of variance (ANOVA) and Bonferroni post-hoc tests were used to detect statistical significances (p<0.05). The mean (SD) fracture resistance (Newtons) for Groups 1 to 4 were: 245.35 (82.69), 390.48 (67.03), 269.69 (10.33), and 418.36 (26.24). The cement type had no statistical significant effect (p>0.05) on fracture resistance within each ceramic system tested. In-Ceram crowns cemented with either glass ionomer or resin cements exhibited a statistically significantly higher fracture-resistance than IPS Empress-2 crowns (p<0.05). Minimal fracture in the test crowns was the common mode exhibited. Fracture resistance of IPS Empress-2 and In-Ceram crowns was not affected by the type of cement used for luting. Both In-Ceram and IPS Empress-2 crowns can be successfully luted with the cements tested with In-Ceram exhibiting higher fracture resistance than IPS Empress-2.

Gender differences in learning physical science concepts: Does computer animation help equalize them?

NASA Astrophysics Data System (ADS)

Jacek, Laura Lee

This dissertation details an experiment designed to identify gender differences in learning using three experimental treatments: animation, static graphics, and verbal instruction alone. Three learning presentations were used in testing of 332 university students. Statistical analysis was performed using ANOVA, binomial tests for differences of proportion, and descriptive statistics. Results showed that animation significantly improved women's long-term learning over static graphics (p = 0.067), but didn't significantly improve men's long-term learning over static graphics. In all cases, women's scores improved with animation over both other forms of instruction for long-term testing, indicating that future research should not abandon the study of animation as a tool that may promote gender equity in science. Short-term test differences were smaller, and not statistically significant. Variation present in short-term scores was related more to presentation topic than treatment. This research also details characteristics of each of the three presentations, to identify variables (e.g. level of abstraction in presentation) affecting score differences within treatments. Differences between men's and women's scores were non-standard between presentations, but these differences were not statistically significant (long-term p = 0.2961, short-term p = 0.2893). In future research, experiments might be better designed to test these presentational variables in isolation, possibly yielding more distinctive differences between presentational scores. Differences in confidence interval overlaps between presentations suggested that treatment superiority may be somewhat dependent on the design or topic of the learning presentation. Confidence intervals greatly overlap in all situations. This undercut, to some degree, the surety of conclusions indicating superiority of one treatment type over the others. However, confidence intervals for animation were smaller, overlapped nearly completely for men and women (there was less overlap between the genders for the other two treatments), and centered around slightly higher means, lending further support to the conclusion that animation helped equalize men's and women's learning. The most important conclusion identified in this research is that gender is an important variable experimental populations testing animation as a learning device. Averages indicated that both men and women prefer to work with animation over either static graphics or verbal instruction alone.

Transtibial vs anatomical single bundle technique for anterior cruciate ligament reconstruction: A Retrospective Cohort Study.

PubMed

Kilinc, Bekir Eray; Kara, Adnan; Oc, Yunus; Celik, Haluk; Camur, Savas; Bilgin, Emre; Erten, Yunus Turgay; Sahinkaya, Turker; Eren, Osman Tugrul

2016-05-01

Most of the ACL reconstruction is done with isometric single-bundle technique. Traditionally, surgeons were trained to use the transtibial technique (TT) for drilling the femoral tunnel. Our study compared the early postoperative period functional and clinical outcomes of patients who had ACL reconstruction with TT and patients who had ACL reconstruction with anatomical single-bundle technique (AT). Fifty-five patients who had ACL reconstruction and adequate follow-up between January 2010-December 2013 were included the study. Patients were grouped by their surgery technique. 28 patients included into anatomical single-bundle ACL reconstruction surgery group (group 1) and 27 patients were included into transtibial AC reconstruction group (group 2). Average age of patients in group 1 and group 2 was 28.3 ± 6, and 27.9 ± 6.4, respectively. Lachman and Pivot-shift tests were performed to patients. Laxity was measured by KT-1000 arthrometer test with 15, 20 and 30 pound power. All patients' muscle strength between both extremities were evaluated with Cybex II (Humac) at 60°/sec, 240°/sec frequencies with flexion and extension peak torque. The maximum force values of non-operated knee and the operated knee were compared to each other. Groups were evaluated by using International Knee Documentation Committee (IKDC) knee ligament healing Standard form, IKDC activity scale, modified Lysholm and Cincinnati evaluation forms. Return to work and exercise time of patients were compared. Functional and clinical outcomes of two groups were compared. NCSS 2007 and PASS 2008 Statistical Software programs were used for statistical analysis. There was no statistically significant difference between Lachman and Pivot-shift results (p > 0.01). Positive value of Pivot-shift test and incidence of anterior translation in Lachman test were higher in the patients who had TT. Lysholm activity level of patients who had TT, 33.3% (n = 9) were excellent, 51.9% (n = 14) were good and 14.8% (n = 4) were moderate; patients who had AT, 57.1% (n = 16) were excellent, 39.3% (n = 11) were good and 3.6% (n = 1) was good level. There was no statistically significant difference between Lysholm Activity level of the patients (p < 0.01). Lysholm Activity level of patients who had AT significantly higher than TT. There was no statistically significant difference between Modified Cincinnati activity level of the patients (p < 0.05). Modified Cincinnati activity level of patients who had AT were significantly higher than those had TT. There was no statistically significant difference between two groups with post treatment IKDC activity level (p < 0.01). Intense activity after treatment rate of patient who had AT was significantly higher than those had TT. There was statistically significant difference between Cybex extension-flexion 60 measurement and extension 240 measurement of the patients (p < 0.01). KT-1000 arthrometer test results with AT was better than the TT in antero-posterior translation of the knee kinematics at 20 and 30 pound of forces. Return to exercise time of patients who had TT was significantly higher than those had AT (p < 0.01). There was no statistically significant difference between return to work time of patients (p > 0.05). Single-bundle anatomic ACL reconstruction was better than the TT in term of clinical, functional, and laboratory results. We believe that AT ACL reconstruction will increase in use and traditional method which is TT ACL reconstruction surgery will decrease in the long term. Theoretically, anatomic relocation of the ACL can provide better knee kinematics. Copyright © 2016 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

Robot-assisted walking training for individuals with Parkinson's disease: a pilot randomized controlled trial.

PubMed

Sale, Patrizio; De Pandis, Maria Francesca; Le Pera, Domenica; Sova, Ivan; Cimolin, Veronica; Ancillao, Andrea; Albertini, Giorgio; Galli, Manuela; Stocchi, Fabrizio; Franceschini, Marco

2013-05-24

Over the last years, the introduction of robotic technologies into Parkinson's disease rehabilitation settings has progressed from concept to reality. However, the benefit of robotic training remains elusive. This pilot randomized controlled observer trial is aimed at investigating the feasibility, the effectiveness and the efficacy of new end-effector robot training in people with mild Parkinson's disease. Design. Pilot randomized controlled trial. Robot training was feasible, acceptable, safe, and the participants completed 100% of the prescribed training sessions. A statistically significant improvement in gait index was found in favour of the EG (T0 versus T1). In particular, the statistical analysis of primary outcome (gait speed) using the Friedman test showed statistically significant improvements for the EG (p = 0,0195). The statistical analysis performed by Friedman test of Step length left (p = 0,0195) and right (p = 0,0195) and Stride length left (p = 0,0078) and right (p = 0,0195) showed a significant statistical gain. No statistically significant improvements on the CG were found. Robot training is a feasible and safe form of rehabilitative exercise for cognitively intact people with mild PD. This original approach can contribute to increase a short time lower limb motor recovery in idiopathic PD patients. The focus on the gait recovery is a further characteristic that makes this research relevant to clinical practice. On the whole, the simplicity of treatment, the lack of side effects, and the positive results from patients support the recommendation to extend the use of this treatment. Further investigation regarding the long-time effectiveness of robot training is warranted. ClinicalTrials.gov NCT01668407.

Correlation between the Quality of Attention and Cognitive Competence with Motor Action in Stroke Patients.

PubMed

Arsic, S; Konstantinovic, Lj; Eminovic, F; Pavlovic, D; Popovic, M B; Arsic, V

2015-01-01

It is considered that cognitive function and attention could affect walking, motion control, and proper conduct during the walk. To determine whether there is a difference in the quality of attention and cognitive ability in stroke patients and patients without neurological damage of similar age and education and to determine whether the connection of attention and cognition affects motor skills, the sample consisted of 50 stroke patients tested with hemiparesis, involved in the process of rehabilitation, and 50 persons, randomly chosen, without neurological damage. The survey used the following tests: Trail Making (TMT A B) test for assessing the flexibility of attention; Mini-Mental State Examination (MMSE) for cognitive status; Functional Ambulation Category (FAC) test to assess the functional status and parameters of walk: speed, frequency, and length of stride; STEP test for assessing the precision of movement and balance. With stroke patients, relationship between age and performance on the MMSE test was marginally significant. The ratio of performance to TMT A B test and years does not indicate statistical significance, while statistical significance between the MMSE test performance and education exists. In stroke patients, performance on MMSE test is correlated with the frequency and length of stride walk. The quality of cognitive function and attention is associated with motor skills but differs in stroke patients and people without neurological damage of similar age. The significance of this correlation can supplement research in neurorehabilitation, improve the quality of medical rehabilitation, and contribute to efficient recovery of these patients.

Using the Coefficient of Determination "R"[superscript 2] to Test the Significance of Multiple Linear Regression

ERIC Educational Resources Information Center

Quinino, Roberto C.; Reis, Edna A.; Bessegato, Lupercio F.

2013-01-01

This article proposes the use of the coefficient of determination as a statistic for hypothesis testing in multiple linear regression based on distributions acquired by beta sampling. (Contains 3 figures.)

A statistical investigation of z test and ROC curve on seismo-ionospheric anomalies in TEC associated earthquakes in Taiwan during 1999-2014

NASA Astrophysics Data System (ADS)

Shih, A. L.; Liu, J. Y. G.

2015-12-01

A median-based method and a z test are employed to find characteristics of seismo-ionospheric precursor (SIP) of the total electron content (TEC) in global ionosphere map (GIM) associated with 129 M≥5.5 earthquakes in Taiwan during 1999-2014. Results show that both negative and positive anomalies in the GIM TEC with the statistical significance of the z test appear few days before the earthquakes. The receiver operating characteristic (ROC) curve is further applied to see whether the SIPs exist in Taiwan.

ON THE SUBJECT OF HYPOTHESIS TESTING

PubMed Central

Ugoni, Antony

1993-01-01

In this paper, the definition of a statistical hypothesis is discussed, and the considerations which need to be addressed when testing a hypothesis. In particular, the p-value, significance level, and power of a test are reviewed. Finally, the often quoted confidence interval is given a brief introduction. PMID:17989768

SOCR Analyses - an Instructional Java Web-based Statistical Analysis Toolkit.

PubMed

Chu, Annie; Cui, Jenny; Dinov, Ivo D

2009-03-01

The Statistical Online Computational Resource (SOCR) designs web-based tools for educational use in a variety of undergraduate courses (Dinov 2006). Several studies have demonstrated that these resources significantly improve students' motivation and learning experiences (Dinov et al. 2008). SOCR Analyses is a new component that concentrates on data modeling and analysis using parametric and non-parametric techniques supported with graphical model diagnostics. Currently implemented analyses include commonly used models in undergraduate statistics courses like linear models (Simple Linear Regression, Multiple Linear Regression, One-Way and Two-Way ANOVA). In addition, we implemented tests for sample comparisons, such as t-test in the parametric category; and Wilcoxon rank sum test, Kruskal-Wallis test, Friedman's test, in the non-parametric category. SOCR Analyses also include several hypothesis test models, such as Contingency tables, Friedman's test and Fisher's exact test.The code itself is open source (http://socr.googlecode.com/), hoping to contribute to the efforts of the statistical computing community. The code includes functionality for each specific analysis model and it has general utilities that can be applied in various statistical computing tasks. For example, concrete methods with API (Application Programming Interface) have been implemented in statistical summary, least square solutions of general linear models, rank calculations, etc. HTML interfaces, tutorials, source code, activities, and data are freely available via the web (www.SOCR.ucla.edu). Code examples for developers and demos for educators are provided on the SOCR Wiki website.In this article, the pedagogical utilization of the SOCR Analyses is discussed, as well as the underlying design framework. As the SOCR project is on-going and more functions and tools are being added to it, these resources are constantly improved. The reader is strongly encouraged to check the SOCR site for most updated information and newly added models.

Biomechanical in vitro - stability testing on human specimens of a locking plate system against conventional screw fixation of a proximal first metatarsal lateral displacement osteotomy.

PubMed

Arnold, Heino; Stukenborg-Colsman, Christina; Hurschler, Christof; Seehaus, Frank; Bobrowitsch, Evgenij; Waizy, Hazibullah

2012-01-01

The aim of this study was to examine resistance to angulation and displacement of the internal fixation of a proximal first metatarsal lateral displacement osteotomy, using a locking plate system compared with a conventional crossed screw fixation. Seven anatomical human specimens were tested. Each specimen was tested with a locking screw plate as well as a crossed cancellous srew fixation. The statistical analysis was performed by the Friedman test. The level of significance was p = 0.05. We found larger stability about all three axes of movement analyzed for the PLATE than the crossed screws osteosynthesis (CSO). The Friedman test showed statistical significance at a level of p = 0.05 for all groups and both translational and rotational movements. The results of our study confirm that the fixation of the lateral proximal first metatarsal displacement osteotomy with a locking plate fixation is a technically simple procedure of superior stability.

Biomechanical In Vitro - Stability Testing on Human Specimens of a Locking Plate System Against Conventional Screw Fixation of a Proximal First Metatarsal Lateral Displacement Osteotomy

PubMed Central

Arnold, Heino; Stukenborg-Colsman, Christina; Hurschler, Christof; Seehaus, Frank; Bobrowitsch, Evgenij; Waizy, Hazibullah

2012-01-01

Introduction: The aim of this study was to examine resistance to angulation and displacement of the internal fixation of a proximal first metatarsal lateral displacement osteotomy, using a locking plate system compared with a conventional crossed screw fixation. Materials and Methodology: Seven anatomical human specimens were tested. Each specimen was tested with a locking screw plate as well as a crossed cancellous srew fixation. The statistical analysis was performed by the Friedman test. The level of significance was p = 0.05. Results: We found larger stability about all three axes of movement analyzed for the PLATE than the crossed screws osteosynthesis (CSO). The Friedman test showed statistical significance at a level of p = 0.05 for all groups and both translational and rotational movements. Conclusion: The results of our study confirm that the fixation of the lateral proximal first metatarsal displacement osteotomy with a locking plate fixation is a technically simple procedure of superior stability. PMID:22675409

The influence of test mode and visuospatial ability on mathematics assessment performance

NASA Astrophysics Data System (ADS)

Logan, Tracy

2015-12-01

Mathematics assessment and testing are increasingly situated within digital environments with international tests moving to computer-based testing in the near future. This paper reports on a secondary data analysis which explored the influence the mode of assessment—computer-based (CBT) and pencil-and-paper based (PPT)—and visuospatial ability had on students' mathematics test performance. Data from 804 grade 6 Singaporean students were analysed using the knowledge discovery in data design. The results revealed statistically significant differences between performance on CBT and PPT test modes across content areas concerning whole number algebraic patterns and data and chance. However, there were no performance differences for content areas related to spatial arrangements geometric measurement or other number. There were also statistically significant differences in performance between those students who possess higher levels of visuospatial ability compared to those with lower levels across all six content areas. Implications include careful consideration for the comparability of CBT and PPT testing and the need for increased attention to the role of visuospatial reasoning in student's mathematics reasoning.

In vitro evaluation of endodontic posts.

PubMed

Drummond, J L

2000-05-01

To compare stainless steel posts and three different fibrous posts with respect to pullout (shear) strength from extracted third molars embedded in denture acrylic. Post space was prepared and the posts cemented with a resin cement according to manufacturer's instructions. Single step and multi-step dentin bonding systems were also evaluated. The testing was in tension at a loading rate of 2 mm/min. The statistical analysis indicated no significant difference in the pullout (shear) strength between any of the post groups tested. Also evaluated was the flexure strength of the fibrous posts before and after thermal cycling. Statistical analysis indicated a significant decrease in flexure strength for the respective fibrous posts following thermal cycling.

A search for spectral lines in gamma-ray bursts using TGRS

NASA Astrophysics Data System (ADS)

Kurczynski, P.; Palmer, D.; Seifert, H.; Teegarden, B. J.; Gehrels, N.; Cline, T. L.; Ramaty, R.; Hurley, K.; Madden, N. W.; Pehl, R. H.

1998-05-01

We present the results of an ongoing search for narrow spectral lines in gamma-ray burst data. TGRS, the Transient Gamma-Ray Spectrometer aboard the Wind satellite is a high energy-resolution Ge device. Thus it is uniquely situated among the array of space-based, burst sensitive instruments to look for line features in gamma-ray burst spectra. Our search strategy adopts a two tiered approach. An automated `quick look' scan searches spectra for statistically significant deviations from the continuum. We analyzed all possible time accumulations of spectra as well as individual spectra for each burst. Follow-up analysis of potential line candidates uses model fitting with F-test and χ2 tests for statistical significance.

Statistical tests of peaks and periodicities in the observed redshift distribution of quasi-stellar objects

NASA Astrophysics Data System (ADS)

Duari, Debiprosad; Gupta, Patrick D.; Narlikar, Jayant V.

1992-01-01

An overview of statistical tests of peaks and periodicities in the redshift distribution of quasi-stellar objects is presented. The tests include the power-spectrum analysis carried out by Burbidge and O'Dell (1972), the generalized Rayleigh test, the Kolmogorov-Smirnov test, and the 'comb-tooth' test. The tests reveal moderate to strong evidence for periodicities of 0.0565 and 0.0127-0.0129. The confidence level of the periodicity of 0.0565 in fact marginally increases when redshifts are transformed to the Galactocentric frame. The same periodicity, first noticed in 1968, persists to date with a QSO population that has since grown about 30 times its original size. The prima facie evidence for periodicities in 1n(1 + z) is found to be of no great significance.

Effect of private versus emergency medical systems transportation in motor vehicle accident victims: Trauma Center Experience in Saudi Arabia.

PubMed

Alshahrani, Mohammed S

2017-01-01

To assess the effect of the mode of transportation of trauma patients (emergency medical service [EMS] vs. non-EMS) on their final clinical outcome in terms of mortality and length of hospital stay. A retrospective study included all patients who were involved in motor vehicle crashes, and who were transferred immediately to an emergency department of a trauma care center from December 2008 to December 2012. Patients were classified into two groups: those brought through EMS and those brought by non-EMS (private transport). Information on demographic characteristics including age and gender was recorded and medical data such as blood pressure, pulse, oxygen saturation, temperature, initial Glasgow Coma Score (GCS), saturation, temperature, initial Glasgow Coma Score (GCS), injury severity score (ISS), and final outcome (discharged or expired) were obtained. Descriptive statistics, mean and standard deviation (SD) were computed for continuous variables and statistical significance was tested by t -test or Mann-Whitney U-test. Categorical variables were described by frequency distribution and percentages; Chi-square or Fisher's exact test as appropriate were employed to test for statistical significance. Logistics regression was performed with mortality as dependent variable and mode of transport and all demographic and prehospital variables as independent variables. A general linear model analysis was performed to test whether the mode of transport was significant to length of hospital stay in EMS and non-EMS clients. Out of 308 patients identified during the study period, 232 were transported through EMS and 76 through non-EMS. The two groups were similar with regard to mortality and length of stay. The crude mortality rate was 30.6% (95% confidence interval [CI]: 24.64-36.53) in the EMS group and 28.9% (95% CI: 18.44-38.76) in the non-EMS group ( p = 0.785). The average length of hospital stay was 9 days (interquartile range [IQR] = 8, 95% CI: 7.3-10.1) for the EMS group and 8 days (IQR = 9.5, 95% CI: 6.7-10.9) for the non-EMS group ( p = 0.803). Multivariate analysis showed that of the study variables, only the injury severity score (ISS) and Glasgow coma score (GCS) were significant to mortality ( p < 0.01), and GCS was more significant to the length of hospital stay ( p < 0.01). There was no significant difference between the EMS and non-EMS groups as they relate to mortality and length of stay in hospital. However, the mortality and length of hospital stay was statistically significant to ISS and GCS.

Role of Text Message Reminder on Oral Hygiene Maintenance of Orthodontic Patients.

PubMed

Kumar, G Sujay; Kashyap, Arpita; Raghav, Shweta; Bhardwaj, Rishibha; Singh, Arunesh; Guram, Guneet

2018-01-01

Fixed orthodontic treatment is frequently associated with increased plaque accumulation leading to gingivitis and white spot lesions (WSLs). This study evaluated the role of text message reminder on oral hygiene of orthodontic patients. A total of 60 patients under fixed orthodontic treatment were randomly divided into two equal groups as control group and study (text message) group. Text message group received reminders about oral hygiene, while the control group did not receive any messages. Oral hygiene of both the groups was evaluated at baseline, 2, and 3 months using plaque indices (PIs) along with WSL status. Data were statistically analyzed using Statistical Package for the Social Sciences (SPSS) statistical software, version 19, with chi-square test and t-test. At the baseline, plaque score was higher in the study group over control group (p > 0.038), whereas it was decreased after 3 months in the test group (p > 0.001). For WSL, there was no significant difference at baseline, but it was significantly lower in study group (p > 0.003). Oral hygiene status improved with text message reminder.

Clinical evaluation of satisfaction in patients rehabilitated with an immediately loaded implant-supported prosthesis: a controlled prospective study.

PubMed

Scala, Rudy; Cucchi, Alessandro; Ghensi, Paolo; Vartolo, Francesco

2012-01-01

The purpose of this controlled prospective study was to compare the satisfaction of patients rehabilitated with an immediately loaded implant-supported prosthesis and patients rehabilitated with a conventional denture in the mandible. Selected mandibular partially or totally edentulous patients were included in this prospective study. Patients' mandibles were completely rehabilitated with immediately loaded implants supporting a screw-retained full-arch prosthesis (test group) or with a conventional denture (control group). The Satisfaction Profile (SAT-P), which investigates a number of psychologic aspects related to the function and esthetics of the stomatognathic apparatus, was administered to each patient 1 month before and 3 months after provisional prosthetic rehabilitation. The questionnaire comprised four different SAT-P items: quality of eating, eating behavior, mood, and self-confidence. A visual analog scale was used to elicit patient responses. SAT-P item scores were analyzed statistically by means of the Student t test and the chi-square test (or the Mann-Whitney nonparametric test), with P < .05 considered significant. Forty-one patients were consecutively treated with 205 immediately loaded implants supporting a screw-retained full-arch prosthesis (test group); 38 patients were consecutively treated with a conventional denture (control group). Statistically significant differences were observed between the test and control groups for all four SAT-P items. The test group reported greater satisfaction for all items versus the control group. In both groups, the differences between pre- and postrehabilitation values were statistically significant. Each patient was satisfied with their treatment outcomes, but patients who received an implant-supported prosthesis were more satisfied than the patients who received a conventional denture. The results suggest that a screw-retained full-arch prosthesis on immediately loaded implants is a predictable means of enhancing patient satisfaction.

Sunflower therapy for children with specific learning difficulties (dyslexia): a randomised, controlled trial.

PubMed

Bull, Leona

2007-02-01

The aim of the study was to determine the clinical and perceived effectiveness of the Sunflower therapy in the treatment of childhood dyslexia. The Sunflower therapy includes applied kinesiology, physical manipulation, massage, homeopathy, herbal remedies and neuro-linguistic programming. A multi-centred, randomised controlled trial was undertaken with 70 dyslexic children aged 6-13 years. The research study aimed to test the research hypothesis that dyslexic children 'feel better' and 'perform better' as a result of treatment by the Sunflower therapy. Children in the treatment group and the control group were assessed using a battery of standardised cognitive, Literacy and self-esteem tests before and after the intervention. Parents of children in the treatment group gave feedback on their experience of the Sunflower therapy. Test scores were compared using the Mann Whitney, and Wilcoxon statistical tests. While both groups of children improved in some of their test scores over time, there were no statistically significant improvements in cognitive or Literacy test performance associated with the treatment. However, there were statistically significant improvements in academic self-esteem, and reading self-esteem, for the treatment group. The majority of parents (57.13%) felt that the Sunflower therapy was effective in the treatment of learning difficulties. Further research is required to verify these findings, and should include a control group receiving a dummy treatment to exclude placebo effects.

Asymptotic Linear Spectral Statistics for Spiked Hermitian Random Matrices

NASA Astrophysics Data System (ADS)

Passemier, Damien; McKay, Matthew R.; Chen, Yang

2015-07-01

Using the Coulomb Fluid method, this paper derives central limit theorems (CLTs) for linear spectral statistics of three "spiked" Hermitian random matrix ensembles. These include Johnstone's spiked model (i.e., central Wishart with spiked correlation), non-central Wishart with rank-one non-centrality, and a related class of non-central matrices. For a generic linear statistic, we derive simple and explicit CLT expressions as the matrix dimensions grow large. For all three ensembles under consideration, we find that the primary effect of the spike is to introduce an correction term to the asymptotic mean of the linear spectral statistic, which we characterize with simple formulas. The utility of our proposed framework is demonstrated through application to three different linear statistics problems: the classical likelihood ratio test for a population covariance, the capacity analysis of multi-antenna wireless communication systems with a line-of-sight transmission path, and a classical multiple sample significance testing problem.

Clinical Comparison of Two Methods of Graft Preparation in Descemet Membrane Endothelial Keratoplasty.

PubMed

Rickmann, Annekatrin; Opitz, Natalia; Szurman, Peter; Boden, Karl Thomas; Jung, Sascha; Wahl, Silke; Haus, Arno; Damm, Lara-Jil; Januschowski, Kai

2018-01-01

Descemet membrane endothelial keratoplasty (DMEK) has been improved over the last decade. The aim of this study was to compare the clinical outcome of the recently introduced liquid bubble method compared to the standard manual preparation. This retrospective study evaluated the outcome of 200 patients after DMEK surgery using two different graft preparation techniques. Ninety-six DMEK were prepared by manual dissection and 104 by the novel liquid bubble technique. The mean follow-up time was 13.7 months (SD ± 8, range 6-36 months). Best corrected mean visual acuity (BCVA) increased for all patients statistically significant from baseline 0.85 logMAR (SD ± 0.5) to 0.26 logMAR (SD ± 0.27) at the final follow-up (Wilcoxon, p = 0.001). Subgroup analyses of BCVA at the final follow-up between manual dissection and liquid bubble preparation showed no statistically significant difference (Mann-Whitney U Test, p = 0.64). The mean central corneal thickness was not statistically different (manual dissection: 539 µm, SD ± 68 µm and liquid bubble technique: 534 µm, SD ± 52 µm,) between the two groups (Mann-Whitney U Test, p = 0.64). At the final follow-up, mean endothelial cell count of donor grafts was statistically not significant different at the final follow-up with 1761 cells/mm 2 (-30.7%, SD ± 352) for manual dissection compared to liquid bubble technique with 1749 cells/mm 2 (-29.9%, SD ± 501) (Mann-Whitney U-Test, p = 0.73). The re-DMEK rate was comparable for manual dissection with 8 cases (8.3%) and 7 cases (6.7%) for liquid bubble dissection (p = 0.69, Chi-Square Test). Regarding the clinical outcome, we did not find a statistical significant difference between manual dissection and liquid bubble graft preparation. Both preparation techniques lead to an equivalent clinical outcome after DMEK surgery.

Improvement of attention span and reaction time with hyperbaric oxygen treatment in patients with toxic injury due to mold exposure.

PubMed

Ezra, N; Dang, K; Heuser, G

2011-01-01

It is, by now, well established that mold toxins (mycotoxins) can cause significant adverse health effects. In this study, 15 subjects who developed an attention deficit disorder (ADD) and slowing of reaction time at the time of exposure to mold toxins were identified. Deficits in attention span and reaction time were documented not only by taking a careful history, but also by performing a Test of Variables of Attention (TOVA). The TOVA test provides an objective measure of these two variables. It was found that mold-exposed subjects show statistically significant decreases in attention span and significant increases in reaction time to stimuli compared to controls. After ten sessions of hyperbaric oxygen treatment (HBOT), a statistically significant improvement was seen in both measures. This preliminary study suggests promising outcomes in treating mold-exposed patients with hyperbaric oxygen.

Improvement of attention span and reaction time with hyperbaric oxygen treatment in patients with toxic injury due to mold exposure

PubMed Central

Ezra, N.; Dang, K.

2010-01-01

It is, by now, well established that mold toxins (mycotoxins) can cause significant adverse health effects. In this study, 15 subjects who developed an attention deficit disorder (ADD) and slowing of reaction time at the time of exposure to mold toxins were identified. Deficits in attention span and reaction time were documented not only by taking a careful history, but also by performing a Test of Variables of Attention (TOVA). The TOVA test provides an objective measure of these two variables. It was found that mold-exposed subjects show statistically significant decreases in attention span and significant increases in reaction time to stimuli compared to controls. After ten sessions of hyperbaric oxygen treatment (HBOT), a statistically significant improvement was seen in both measures. This preliminary study suggests promising outcomes in treating mold-exposed patients with hyperbaric oxygen. PMID:20978814

Preprocedural Anxiety and Pain Perception Following Root Surface Debridement in Chronic Periodontitis Patients.

PubMed

Naik, Vanaja Krishna; Balasundaram, Aruna; Appukuttan, Devapriya; Nainar, Deepavalli Arumuga; Milward, Michael Robert; Victor, Dhayanand John; Junaid, Mohammed

2018-01-01

The aim of this study was to evaluate and compare preprocedural dental anxiety levels and postprocedural pain perception in chronic periodontitis patients during conventional-staged root surface debridement (RSD) and single-stage RSD. Thirty-seven adult generalized chronic periodontitis patients requiring RSD were recruited in this study. Preprocedural anxiety levels were assessed using a self-reported questionnaire and postprocedural pain perceptions were assessed using 0-10 cm visual analog scale. The subject population was divided into two groups: staged RSD ( n = 18) and single-stage RSD ( n = 19). Staged RSD patients visited four times as opposed to single-stage RSD patients. Data were subjected to Pearson Chi-square test, Mann-Whitney U-test, and Spearman's rank correlation. There was no statistically significant difference in dental anxiety levels or pain perceptions in both the groups. Within Group 1, there was statistical significant difference in dental anxiety levels between visit 4 and visit 3 ( P = 0.037) and pain perception between visit 3 and visit 1 ( P = 0.005), visit 4 and visit 1 ( P = 0.002), and visit 4 and visit 2 (0.04) was statistically significant. There was a positive correlation of anxiety questionnaire (Q1-Q4) to the pain score in Group 1 which was statistically significant and in single-stage RSD. Conventional quadrant-wise RSD tends to cognitively condition the anxiety experience thus influencing pain experience.

Using the Coefficient of Confidence to Make the Philosophical Switch from a Posteriori to a Priori Inferential Statistics

ERIC Educational Resources Information Center

Trafimow, David

2017-01-01

There has been much controversy over the null hypothesis significance testing procedure, with much of the criticism centered on the problem of inverse inference. Specifically, p gives the probability of the finding (or one more extreme) given the null hypothesis, whereas the null hypothesis significance testing procedure involves drawing a…

Exploring the Replicability of a Study's Results: Bootstrap Statistics for the Multivariate Case.

ERIC Educational Resources Information Center

Thompson, Bruce

Conventional statistical significance tests do not inform the researcher regarding the likelihood that results will replicate. One strategy for evaluating result replication is to use a "bootstrap" resampling of a study's data so that the stability of results across numerous configurations of the subjects can be explored. This paper…

Comparing the Lifetimes of Two Brands of Batteries

ERIC Educational Resources Information Center

Dunn, Peter K.

2013-01-01

In this paper, we report a case study that illustrates the importance in interpreting the results from statistical tests, and shows the difference between practical importance and statistical significance. This case study presents three sets of data concerning the performance of two brands of batteries. The data are easy to describe and…

The longevity of statistical learning: When infant memory decays, isolated words come to the rescue.

PubMed

Karaman, Ferhat; Hay, Jessica F

2018-02-01

Research over the past 2 decades has demonstrated that infants are equipped with remarkable computational abilities that allow them to find words in continuous speech. Infants can encode information about the transitional probability (TP) between syllables to segment words from artificial and natural languages. As previous research has tested infants immediately after familiarization, infants' ability to retain sequential statistics beyond the immediate familiarization context remains unknown. Here, we examine infants' memory for statistically defined words 10 min after familiarization with an Italian corpus. Eight-month-old English-learning infants were familiarized with Italian sentences that contained 4 embedded target words-2 words had high internal TP (HTP, TP = 1.0) and 2 had low TP (LTP, TP = .33)-and were tested on their ability to discriminate HTP from LTP words using the Headturn Preference Procedure. When tested after a 10-min delay, infants failed to discriminate HTP from LTP words, suggesting that memory for statistical information likely decays over even short delays (Experiment 1). Experiments 2-4 were designed to test whether experience with isolated words selectively reinforces memory for statistically defined (i.e., HTP) words. When 8-month-olds were given additional experience with isolated tokens of both HTP and LTP words immediately after familiarization, they looked significantly longer on HTP than LTP test trials 10 min later. Although initial representations of statistically defined words may be fragile, our results suggest that experience with isolated words may reinforce the output of statistical learning by helping infants create more robust memories for words with strong versus weak co-occurrence statistics. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

ANTIPLAQUE AND ANTIGINGIVITIS EFFECT OF LIPPIA SIDOIDES. A DOUBLE-BLIND CLINICAL STUDY IN HUMANS

PubMed Central

Rodrigues, Ítalo Sarto Carvalho; Tavares, Vinícius Nascimento; Pereira, Sérgio Luís da Silva; da Costa, Flávio Nogueira

2009-01-01

Objectives: The antiplaque and antigingivitis effect of Lippia Sidoides (LS) was evaluated in this in vivo investigation. Material and Methods: Twenty-three subjects participated in a cross-over, double-blind clinical study, using 21-day partial-mouth experimental model of gingivitis. A toothshield was constructed for each volunteer, avoiding the brushing of the 4 experimental posterior teeth in the lower left quadrant. The subjects were randomly assigned initially to use either the placebo gel (control group) or the test gel, containing 10% LS (test group). Results: The clinical results showed statistically significant differences for plaque index (PLI) (p<0.01) between days 0 and 21 in both groups, however only the control group showed statistically significant difference (p<0.01) for the bleeding (IB) and gingival (GI) index within the experimental period of 21 days. On day 21, the test group presented significantly better results than the control group with regard to the GI (p<0.05). Conclusions: The test gel containing 10% LS was effective in the control of gingivitis. PMID:19936516

Temporal changes and variability in temperature series over Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Suhaila, Jamaludin

2015-02-01

With the current concern over climate change, the descriptions on how temperature series changed over time are very useful. Annual mean temperature has been analyzed for several stations over Peninsular Malaysia. Non-parametric statistical techniques such as Mann-Kendall test and Theil-Sen slope estimation are used primarily for assessing the significance and detection of trends, while a nonparametric Pettitt's test and sequential Mann-Kendall test are adopted to detect any abrupt climate change. Statistically significance increasing trends for annual mean temperature are detected for almost all studied stations with the magnitude of significant trend varied from 0.02°C to 0.05°C per year. The results shows that climate over Peninsular Malaysia is getting warmer than before. In addition, the results of the abrupt changes in temperature using Pettitt's and sequential Mann-Kendall test reveal the beginning of trends which can be related to El Nino episodes that occur in Malaysia. In general, the analysis results can help local stakeholders and water managers to understand the risks and vulnerabilities related to climate change in terms of mean events in the region.

[The growth behavior of mouse fibroblasts on intraocular lens surface of various silicone and PMMA materials].

PubMed

Kammann, J; Kreiner, C F; Kaden, P

1994-08-01

Experience with intraocular lenses (IOL) made of PMMA dates back ca. 40 years, while silicone IOLs have been in use for only about 10 years. The biocompatibility of PMMA and silicone caoutchouc was tested in a comparative study investigating the growth of mouse fibroblasts on different IOL materials. Spectrophotometric determination of protein synthesis and liquid scintillation counting of DNA synthesis were carried out. The spreading of cells was planimetrically determined, and the DNA synthesis of individual cells in direct contact with the test sample was tested. The results showed that the biocompatibility of silicone lenses made of purified caoutchouc is comparable with that of PMMA lenses; there is no statistically significant difference. However, impurities arising during material synthesis result in a statistically significant inhibition of cell growth on the IOL surfaces.

Evaluation of Supercritical Extracts of Algae as Biostimulants of Plant Growth in Field Trials.

PubMed

Michalak, Izabela; Chojnacka, Katarzyna; Dmytryk, Agnieszka; Wilk, Radosław; Gramza, Mateusz; Rój, Edward

2016-01-01

The aim of the field trials was to determine the influence of supercritical algal extracts on the growth and development of winter wheat (variety Akteur ). As a raw material for the supercritical fluid extraction, the biomass of microalga Spirulina plantensis , brown seaweed - Ascophyllum nodosum and Baltic green macroalgae was used. Forthial and Asahi SL constituted the reference products. It was found that the tested biostimulants did not influence statistically significantly the plant height, length of ear, and shank length. The ear number per m 2 was the highest in the group where the Baltic macroalgae extract was applied in the dose 1.0 L/ha (statistically significant differences). Number of grains in ear (statistically significant differences) and shank length was the highest in the group treated with Spirulina at the dose 1.5 L/ha. In the group with Ascophyllum at the dose 1.0 L/ha, the highest length of ear was observed. The yield was comparable in all the experimental groups (lack of statistically significant differences). Among the tested supercritical extracts, the best results were obtained for Spirulina (1.5 L/ha). The mass of 1000 grains was the highest for extract from Baltic macroalgae and was 3.5% higher than for Asahi, 4.0% higher than for Forthial and 18.5% higher than for the control group (statistically significant differences). Future work is needed to fully characterize the chemical composition of the applied algal extracts. A special attention should be paid to the extracts obtained from Baltic algae because they are inexpensive source of naturally occurring bioactive compounds, which can be used in sustainable agriculture and horticulture.

Evaluation of Supercritical Extracts of Algae as Biostimulants of Plant Growth in Field Trials

PubMed Central

Michalak, Izabela; Chojnacka, Katarzyna; Dmytryk, Agnieszka; Wilk, Radosław; Gramza, Mateusz; Rój, Edward

2016-01-01

The aim of the field trials was to determine the influence of supercritical algal extracts on the growth and development of winter wheat (variety Akteur). As a raw material for the supercritical fluid extraction, the biomass of microalga Spirulina plantensis, brown seaweed – Ascophyllum nodosum and Baltic green macroalgae was used. Forthial and Asahi SL constituted the reference products. It was found that the tested biostimulants did not influence statistically significantly the plant height, length of ear, and shank length. The ear number per m2 was the highest in the group where the Baltic macroalgae extract was applied in the dose 1.0 L/ha (statistically significant differences). Number of grains in ear (statistically significant differences) and shank length was the highest in the group treated with Spirulina at the dose 1.5 L/ha. In the group with Ascophyllum at the dose 1.0 L/ha, the highest length of ear was observed. The yield was comparable in all the experimental groups (lack of statistically significant differences). Among the tested supercritical extracts, the best results were obtained for Spirulina (1.5 L/ha). The mass of 1000 grains was the highest for extract from Baltic macroalgae and was 3.5% higher than for Asahi, 4.0% higher than for Forthial and 18.5% higher than for the control group (statistically significant differences). Future work is needed to fully characterize the chemical composition of the applied algal extracts. A special attention should be paid to the extracts obtained from Baltic algae because they are inexpensive source of naturally occurring bioactive compounds, which can be used in sustainable agriculture and horticulture. PMID:27826310

Tryptophan Hydroxylase 2 Gene Polymorphism in Anxiety and Depressive Disorder in Kashmiri Population

PubMed Central

Shoib, Sheikh; Shah, Tabindah; Mushtaq, Sahil

2014-01-01

Background: The gene of tryptophan hydroxylase is widely recognized as a major candidate gene in many psychiatric disorders. However, no study has been done which investigates tryptophan hydroxylase 2 gene polymorphism in anxiety and depressive disorders in Kashmiri population (India). Objectives: To study tryptophan hydroxylase 2 (TPH2) C 11993 A gene polymorphism in anxiety and depressive disorders. Method: Sixty patients of depression disorder, 60 patients of anxiety disorder and 40 unrelated healthy volunteers (control) were studied in a case control design. Polymorphism was determined using polymerase chain reaction (PCR) and agarose gel electrophoresis after digestion with HAP II enzyme. Genotypes and allele frequencies were compared using Chi-square tests, Fischer’s exact test, odds ratio, 95% confidence interval (C.I) and p-value of <0.05 was considered to be statistical significant. Results: The mean age ± SD of anxiety, depression and control group was 32.73±10.99, 32.20±10 and 29.75±10.12 respectively and the difference was found to be statistically non significant (p=0.349).The mean HAM-A (Hamilton rating scale for anxiety) score and HAM-D (Hamilton rating scale for depression) score was high in both groups (anxiety and depression) and found to be statistically significant (p=0.001).Depression group had AA genotype (55.2%) than control (37.5%) and was found to be statistically non significant (p=0.890).Comparison of allelic frequency revealed no association of A allele in anxiety group (76.67%) compared with control (75.5%) and was found to be statistically non significant (p= 0.866), OR 1.09 (0.56-2.11). Conclusion: TPH2C 11993 A gene was not found to be associated with major depressive disorder (MDD) and anxiety disorder in Kashmiri population. PMID:25121048

PROMISE: a tool to identify genomic features with a specific biologically interesting pattern of associations with multiple endpoint variables.

PubMed

Pounds, Stan; Cheng, Cheng; Cao, Xueyuan; Crews, Kristine R; Plunkett, William; Gandhi, Varsha; Rubnitz, Jeffrey; Ribeiro, Raul C; Downing, James R; Lamba, Jatinder

2009-08-15

In some applications, prior biological knowledge can be used to define a specific pattern of association of multiple endpoint variables with a genomic variable that is biologically most interesting. However, to our knowledge, there is no statistical procedure designed to detect specific patterns of association with multiple endpoint variables. Projection onto the most interesting statistical evidence (PROMISE) is proposed as a general procedure to identify genomic variables that exhibit a specific biologically interesting pattern of association with multiple endpoint variables. Biological knowledge of the endpoint variables is used to define a vector that represents the biologically most interesting values for statistics that characterize the associations of the endpoint variables with a genomic variable. A test statistic is defined as the dot-product of the vector of the observed association statistics and the vector of the most interesting values of the association statistics. By definition, this test statistic is proportional to the length of the projection of the observed vector of correlations onto the vector of most interesting associations. Statistical significance is determined via permutation. In simulation studies and an example application, PROMISE shows greater statistical power to identify genes with the interesting pattern of associations than classical multivariate procedures, individual endpoint analyses or listing genes that have the pattern of interest and are significant in more than one individual endpoint analysis. Documented R routines are freely available from www.stjuderesearch.org/depts/biostats and will soon be available as a Bioconductor package from www.bioconductor.org.

Revised standards for statistical evidence.

PubMed

Johnson, Valen E

2013-11-26

Recent advances in Bayesian hypothesis testing have led to the development of uniformly most powerful Bayesian tests, which represent an objective, default class of Bayesian hypothesis tests that have the same rejection regions as classical significance tests. Based on the correspondence between these two classes of tests, it is possible to equate the size of classical hypothesis tests with evidence thresholds in Bayesian tests, and to equate P values with Bayes factors. An examination of these connections suggest that recent concerns over the lack of reproducibility of scientific studies can be attributed largely to the conduct of significance tests at unjustifiably high levels of significance. To correct this problem, evidence thresholds required for the declaration of a significant finding should be increased to 25-50:1, and to 100-200:1 for the declaration of a highly significant finding. In terms of classical hypothesis tests, these evidence standards mandate the conduct of tests at the 0.005 or 0.001 level of significance.

Pisces did not have increased heart failure: data-driven comparisons of binary proportions between levels of a categorical variable can result in incorrect statistical significance levels.

PubMed

Austin, Peter C; Goldwasser, Meredith A

2008-03-01

We examined the impact on statistical inference when a chi(2) test is used to compare the proportion of successes in the level of a categorical variable that has the highest observed proportion of successes with the proportion of successes in all other levels of the categorical variable combined. Monte Carlo simulations and a case study examining the association between astrological sign and hospitalization for heart failure. A standard chi(2) test results in an inflation of the type I error rate, with the type I error rate increasing as the number of levels of the categorical variable increases. Using a standard chi(2) test, the hospitalization rate for Pisces was statistically significantly different from that of the other 11 astrological signs combined (P=0.026). After accounting for the fact that the selection of Pisces was based on it having the highest observed proportion of heart failure hospitalizations, subjects born under the sign of Pisces no longer had a significantly higher rate of heart failure hospitalization compared to the other residents of Ontario (P=0.152). Post hoc comparisons of the proportions of successes across different levels of a categorical variable can result in incorrect inferences.

Statistical analysis of the electrocatalytic activity of Pt nanoparticles supported on novel functionalized reduced graphene oxide-chitosan for methanol electrooxidation

NASA Astrophysics Data System (ADS)

Ekrami-Kakhki, Mehri-Saddat; Abbasi, Sedigheh; Farzaneh, Nahid

2018-01-01

The purpose of this study is to statistically analyze the anodic current density and peak potential of methanol oxidation at Pt nanoparticles supported on functionalized reduced graphene oxide (RGO), using design of experiments methodology. RGO is functionalized with methyl viologen (MV) and chitosan (CH). The novel Pt/MV-RGO-CH catalyst is successfully prepared and characterized with transmission electron microscopy (TEM) image. The electrocatalytic activity of Pt/MV-RGOCH catalyst is experimentally evaluated for methanol oxidation. The effects of methanol concentration and scan rate factors are also investigated experimentally and statistically. The effects of these two main factors and their interactions are investigated, using analysis of variance test, Duncan's multiple range test and response surface method. The results of the analysis of variance show that all the main factors and their interactions have a significant effect on anodic current density and peak potential of methanol oxidation at α = 0.05. The suggested models which encompass significant factors can predict the variation of the anodic current density and peak potential of methanol oxidation. The results of Duncan's multiple range test confirmed that there is a significant difference between the studied levels of the main factors. [Figure not available: see fulltext.

Determining the relationship between atherosclerosis and periodontopathogenic microorganisms in chronic periodontitis patients.

PubMed

Bozoglan, Alihan; Ertugrul, Abdullah Seckin; Taspınar, Mehmet; Yuzbasioglu, Betul

2017-05-01

The aim of this study is to determine the relationship between atherosclerosis and periodontopathogenic microorganisms in chronic periodontitis patients following periodontal treatment. A total of 40 patients were included in the study. 20 of these patients diagnosed with atherosclerosis and chronic periodontitis formed the test group. The remaining 20 patients were systemically healthy patients diagnosed with chronic periodontitis and formed the control group. All patients had nonsurgical periodontal treatment. The periodontopathogenic microorganism levels were determined at baseline and at 6 months in microbial dental plaque samples and WBC, LDL, HDL, PLT, fibrinogen, creatinine and hs-CRP levels were determined by blood samples. Statistically significant reduction has been achieved in clinical periodontal parameters following non-surgical periodontal treatment in test and control groups. Following periodontal treatment, WBC, LDL, PLT, fibrinogen, creatinine and hs-CRP levels significantly decreased and HDL levels significantly increased in both test and control groups. Similarly, the periodontopathogenic microorganism levels significantly decreased following periodontal treatment in the test and control groups. A statistically significant positive correlation has been determined between the periodontopathogenic microorganism levels and WBC, LDL, PLT, fibrinogen, creatinine, and hs-CRP levels in the test group. The association between hs-CRP, WBC, LDL, PLT, fibrinogen, creatinine, and the amount of periodontopathogenic microorganisms indicates the possibility that periodontal treatment could decrease the risk atherosclerosis. More studies must be conducted in order for these results to be supported.

Association among Working Hours, Occupational Stress, and Presenteeism among Wage Workers: Results from the Second Korean Working Conditions Survey.

PubMed

Jeon, Sung-Hwan; Leem, Jong-Han; Park, Shin-Goo; Heo, Yong-Seok; Lee, Bum-Joon; Moon, So-Hyun; Jung, Dal-Young; Kim, Hwan-Cheol

2014-03-24

The purpose of the present study was to identify the association between presenteeism and long working hours, shiftwork, and occupational stress using representative national survey data on Korean workers. We analyzed data from the second Korean Working Conditions Survey (KWCS), which was conducted in 2010, in which a total of 6,220 wage workers were analyzed. The study population included the economically active population aged above 15 years, and living in the Republic of Korea. We used the chi-squared test and multivariate logistic regression to test the statistical association between presenteeism and working hours, shiftwork, and occupational stress. Approximately 19% of the workers experienced presenteeism during the previous 12 months. Women had higher rates of presenteeism than men. We found a statistically significant dose-response relationship between working hours and presenteeism. Shift workers had a slightly higher rate of presenteeism than non-shift workers, but the difference was not statistically significant. Occupational stress, such as high job demand, lack of rewards, and inadequate social support, had a significant association with presenteeism. The present study suggests that long working hours and occupational stress are significantly related to presenteeism.

Association among Working Hours, Occupational Stress, and Presenteeism among Wage Workers: Results from the Second Korean Working Conditions Survey

PubMed Central

2014-01-01

Objectives The purpose of the present study was to identify the association between presenteeism and long working hours, shiftwork, and occupational stress using representative national survey data on Korean workers. Methods We analyzed data from the second Korean Working Conditions Survey (KWCS), which was conducted in 2010, in which a total of 6,220 wage workers were analyzed. The study population included the economically active population aged above 15 years, and living in the Republic of Korea. We used the chi-squared test and multivariate logistic regression to test the statistical association between presenteeism and working hours, shiftwork, and occupational stress. Results Approximately 19% of the workers experienced presenteeism during the previous 12 months. Women had higher rates of presenteeism than men. We found a statistically significant dose–response relationship between working hours and presenteeism. Shift workers had a slightly higher rate of presenteeism than non-shift workers, but the difference was not statistically significant. Occupational stress, such as high job demand, lack of rewards, and inadequate social support, had a significant association with presenteeism. Conclusions The present study suggests that long working hours and occupational stress are significantly related to presenteeism. PMID:24661575

Comparison between two surgical techniques for root coverage with an acellular dermal matrix graft.

PubMed

Andrade, Patrícia F; Felipe, Maria Emília M C; Novaes, Arthur B; Souza, Sérgio L S; Taba, Mário; Palioto, Daniela B; Grisi, Márcio F M

2008-03-01

The aim of this randomized, controlled, clinical study was to compare two surgical techniques with the acellular dermal matrix graft (ADMG) to evaluate which technique could provide better root coverage. Fifteen patients with bilateral Miller Class I gingival recession areas were selected. In each patient, one recession area was randomly assigned to the control group, while the contra-lateral recession area was assigned to the test group. The ADMG was used in both groups. The control group was treated with a broader flap and vertical-releasing incisions, and the test group was treated with the proposed surgical technique, without releasing incisions. The clinical parameters evaluated before the surgeries and after 12 months were: gingival recession height, probing depth, relative clinical attachment level and the width and thickness of keratinized tissue. There were no statistically significant differences between the groups for all parameters at baseline. After 12 months, there was a statistically significant reduction in recession height in both groups, and there was no statistically significant difference between the techniques with regard to root coverage. Both surgical techniques provided significant reduction in gingival recession height after 12 months, and similar results in relation to root coverage.

Changes in the oral environment after placement of lingual and labial orthodontic appliances.

PubMed

Lombardo, Luca; Ortan, Yildiz Öztürk; Gorgun, Özge; Panza, Chiara; Scuzzo, Giuseppe; Siciliani, Giuseppe

2013-09-11

This study compared the oral hygiene and caries risk of patients treated with labial and lingual orthodontic appliances throughout a prospective evaluation of the status of the oral environment before and after bracket placement. A total of 20 orthodontic patients aged 19 to 23 years were included in the study and were divided into two groups: 10 patients wore Roth labial appliance (American Orthodontics, Sheboygan, WI, USA) and 10 patients wore STb lingual appliance (Ormco Corporation, Glendora, CA, USA). Plaque index (PI), gingival bleeding index (GBI), salivary flow rate, saliva buffer capacity, salivary pH, and Streptococcus mutans and Lactobacillus counts in saliva were determined at three time points: before orthodontic appliance placement (T0), 4 weeks after bonding (T1), and 8 weeks after bonding (T2). After appliance placement, all patients were periodically educated to the oral hygiene procedures. Wilcoxon rank and Mann-Whitney U tests were used to determine intragroup and intergroup differences as regards qualitative data. To compare quantitative data between the groups, chi-square and Fisher's exact tests were undertaken, while intragroup differences were tested with McNemar test. The level of statistical significance was set at p<0.05. Statistical analysis of the data obtained revealed a statistically significant difference between the data of T0 and T1 and the data of T0 and T2 of the PI scores and between T0 and T2 of the GBI scores in the group treated with the lingual appliance. The GBI value increased significantly between T0 and T1 but decreased significantly between T1 and T2 (p<0.01) in the group treated with labial appliance. S. mutans counts increased significantly between T0 and T2 in the saliva samples of patients treated with lingual appliance. No statistically significant differences were found between S. mutans and Lactobacillus counts at the three terms of saliva collection in patients treated with labial appliance. No statistically significant differences were found between the two groups at the three time points as regards the salivary flow rate and saliva buffer capacity. Lingual and labial orthodontic appliances showed a different potential in modifying the investigated clinical parameters: patients wearing STb lingual orthodontic appliance had more plaque retention 4 and 8 weeks after bonding, while there were more gingival inflammation and more S. mutans counts 8 weeks after bonding. No differences were found between the two groups as regards the Lactobacillus counts, the salivary flow rate, and saliva buffer capacity.

Addressing astronomy misconceptions and achieving national science standards utilizing aspects of multiple intelligences theory in the classroom and the planetarium

NASA Astrophysics Data System (ADS)

Sarrazine, Angela Renee

The purpose of this study was to incorporate multiple intelligences techniques in both a classroom and planetarium setting to create a significant increase in student learning about the moon and lunar phases. Utilizing a free-response questionnaire and a 25 item multiple choice pre-test/post-test design, this study identified middle school students' misconceptions and measured increases in student learning about the moon and lunar phases. The study spanned two semesters and contained six treatment groups which consisted of both single and multiple interventions. One group only attended the planetarium program. Two groups attended one of two classes a week prior to the planetarium program, and two groups attended one of two classes a week after the planetarium program. The most rigorous treatment group attended a class both a week before and after the planetarium program. Utilizing Rasch analysis techniques and parametric statistical tests, all six groups exhibited statistically significant gains in knowledge at the 0.05 level. There were no significant differences between students who attended only a planetarium program versus a single classroom program. Also, subjects who attended either a pre-planetarium class or a post- planetarium class did not show a statistically significant gain over the planetarium only situation. Equivalent effects on student learning were exhibited by the pre-planetarium class groups and post-planetarium class groups. Therefore, it was determined that the placement of the second intervention does not have a significant impact on student learning. However, a decrease in learning was observed with the addition of a third intervention. Further instruction and testing appeared to hinder student learning. This is perhaps an effect of subject fatigue.

Clinical evaluation of flowable resins in non-carious cervical lesions: two-year results.

PubMed

Celik, Cigdem; Ozgünaltay, Gül; Attar, Nuray

2007-01-01

This study evaluated the two-year clinical performance of one microhybrid composite and three different types of flowable resin materials in non-carious cervical lesions. A total of 252 noncarious cervical lesions were restored in 37 patients (12 male, 25 female) with Admira Flow, Dyract Flow, Filtek Flow and Filtek Z250, according to manufacturers' instructions. All the restorations were placed by one operator, and two other examiners evaluated the restorations clinically within one week after placement and after 6, 12, 18 and 24 months, using modified USPHS criteria. At the end of 24 months, 172 restorations were evaluated in 26 patients, with a recall rate of 68%. Statistical analysis was completed using the Pearson Chi-square and Fisher-Freeman-Halton tests (p < 0.05). Additionally, survival rates were analyzed with the Kaplan-Meier estimator and the Log-Rank test (p < 0.05). The Log-Rank test indicated statistically significant differences between the survival rates of Dyract Flow/Admira Flow and Dyract Flow/Filtek Z250 (p < 0.05). While there was a statistically significant difference between Dyract Flow and the other materials for color match at 12 and 18 months, no significant difference was observed among all of the materials tested at 24 months. Significant differences were revealed between Filtek Z250 and the other materials for marginal adaptation at 18 and 24 months (p < 0.05). With respect to marginal discoloration, secondary caries, surface texture and anatomic form, no significant differences were found between the resin materials (p > 0.05). It was concluded that different types of resin materials demonstrated acceptable clinical performance in non-carious cervical lesions, except for the retention rates of the Dyract Flow restorations.

Evaluation of children's dental anxiety levels at a kindergarten and at a dental clinic.

PubMed

Kilinç, Gulser; Akay, Aynur; Eden, Ece; Sevinç, Nilgün; Ellidokuz, Hülya

2016-08-18

This study evaluated the dental anxiety levels of preschool children at a kindergarten and at a dental clinic. The anxiety levels of ninety 4-6-year-old (4.99 ± 0.81) preschool children were evaluated according to pulse rates, the facial image scale (FIS), the Venham picture test (VPT), and the Frankl behavior rating scale. The children's mothers were asked to complete the state-trait anxiety inventory (STAI) forms 1 and 2 (STAI 2 and STAI 2). The sample t-test, Mann-Whitney U test, and Pearson's correlation test were used. A statistically significant difference was observed between the children's pulse rates when measured at the dental clinic and those when measured at the kindergarten (p < 0.001). Although the results were not statistically significant, more negative facial expressions were observed in the children at the dental clinic than in those at the kindergarten when assessed using FIS and VPT (p = 0.090 and p = 0.108, respectively). There was a statistically significant correlation between the transient anxiety levels (STAI 1) of mothers and the VPT scores of their children evaluated at the dental clinic (r = 0.506, p < 0.001). The continuous anxiety level of the mothers of males was found to be significantly higher (p = 0.033) than that of the mothers of females (STAI 2). Although the children had been informed about dentistry and were introduced to a dentist at the kindergarten, their anxiety levels seemingly increased as they arrived at the dental clinic. The significant increase observed in the children's pulse rates was a physical indicator that their anxiety levels had increased. It can be concluded that the children felt more anxious at the dental clinic that at the kindergarten.

PA02.22. Hypolipidemic effect of different coconut oil extracts of vyosakatvivaradi formulation in wistar rats.

PubMed Central

Mahapatra, Anita; Rajurkar, Sudhir; Eranezhath, Sujith; Manohar, Ram

2013-01-01

Purpose: To study the preventive and therapeutic Hypolipidemic effect of different coconut oil extracts of Vyosakatvivaradi formulation. Method: High fat diet was fed for 21 days to induce Hyperlipidemia. 110 weanling wistar rats randomly divided in to Eleven groups, four in treatment, four in preventive group, two control and one standarad group. Four test drugs – 1. VCO (virgin coconut oil) + HERBS, 2. TCO (Traditional coconut oil) + HERBS, 3. CCO (Commercial coconut oil) + HERBS, 4. TCO + Coconut Milk + HERBS were administered at the dose rate of 0.06ml tid orally for 28 days in treatment group and 28 days in preventive group from the day one of experiment and the results were compared with Simvastatin 10 mg. All the animals were anesthetized using anesthetic ether and pooled blood samples from each group were collected on day Zero, day 21st and on termination day i.e. day 28th after start of actual treatment. Result: Animals in all groups did not reveal any change in their behavior or visible adverse reaction throughout the experimental period. Statistically significant reduction in mean triglyceride values in test drug -4 animals revealed preventive. Statistically significant reduction in the mean cholesterol level (mg/dl) was observed in test drug -4 animals. Statistically significant increase in the mean HDL level 5% level of significance was observed in preventive dose of test drug 3. Microscopic observations of liver, kidney and aorta revealed no significant change. Conclusion: The medicated oil “CCO + HERBS” and TCO + Coconut Milk + HERBS” showed encouraging therapeutic and preventive effects on hyperlipidemia. However, the oil “TCO + Coconut Milk + HERBS” is observed to be better than the oil CCO + HERBS. Though the oils “VCO + HERBS” and “TCO + HERBS” exhibited moderate hypolipidemic action.

The resolving power of in vitro genotoxicity assays for cigarette smoke particulate matter.

PubMed

Scott, K; Saul, J; Crooks, I; Camacho, O M; Dillon, D; Meredith, C

2013-06-01

In vitro genotoxicity assays are often used to compare tobacco smoke particulate matter (PM) from different cigarettes. The quantitative aspect of the comparisons requires appropriate statistical methods and replication levels, to support the interpretation in terms of power and significance. This paper recommends a uniform statistical analysis for the Ames test, mouse lymphoma mammalian cell mutation assay (MLA) and the in vitro micronucleus test (IVMNT); involving a hierarchical decision process with respect to slope, fixed effect and single dose comparisons. With these methods, replication levels of 5 (Ames test TA98), 4 (Ames test TA100), 10 (Ames test TA1537), 6 (MLA) and 4 (IVMNT) resolved a 30% difference in PM genotoxicity. Copyright © 2013 Elsevier Ltd. All rights reserved.

Receptor activator of nuclear factor kappa B ligand and osteoprotegerin levels in gingival crevicular fluid

PubMed Central

Sarlati, Fatemeh; Sattari, Mandana; Razzaghi, Shilan; Nasiri, Malihe

2012-01-01

Background: Osteoclastogenesis is coordinated by the interaction of three members of the tumor necrosis factor (TNF) superfamily: Osteoprotegerin (OPG)/receptor activator of nuclear factor kappa B ligand (RANKL)/receptor activator of nuclear factor kappa B (RANK). The aim of this study was to investigate RANKL and OPG levels, and their relative ratio in gingival crevicular fluid (GCF) of patients with chronic and aggressive periodontitis, as well as healthy controls. Materials and Methods: In this analytical study, GCF was obtained from healthy (n = 10), mild chronic periodontitis (n = 18), moderate chronic periodontitis (n = 18), severe chronic periodontitis (n = 20), and generalized aggressive periodontitis (n = 20) subjects. RANKL and OPG concentrations were measured by enzyme-linked immunosorbent assay. Statistical tests used were Kruskal–Wallis test, Mann–Whitney U rank sum test, and Spearman's rank correlation analysis. The level of statistical significance was set at P < 0.05. Results: Mean RANKL concentration showed no statistically significant differences between groups (P = 0.58). There were also no significant differences between mean OPG concentration in the five groups (P = 0.0.56). Moreover, relative RANKL/OPG ratio did not reveal a significant difference between the three study group subjects: healthy, chronic periodontitis (mild, moderate, severe), and aggressive periodontitis (P = 0.41). There was statistically significant correlation between the concentration of sRANKL and Clinical Attachment Level (CAL) in moderate chronic periodontitis patients (R = 0.48, P = 0.04). There was also negative correlation between OPG concentration and CAL in moderate chronic periodontitis patients, although not significant (R = −0.13). Conclusion: RANKL was prominent in periodontitis sites, especially in moderate periodontitis patients, whereas OPG was not detectable in some diseased sites with bleeding on probing, supporting the role of these two molecules in the bone loss developed in this disease. PMID:23559954

Predictive capacity of a non-radioisotopic local lymph node assay using flow cytometry, LLNA:BrdU-FCM: Comparison of a cutoff approach and inferential statistics.

PubMed

Kim, Da-Eun; Yang, Hyeri; Jang, Won-Hee; Jung, Kyoung-Mi; Park, Miyoung; Choi, Jin Kyu; Jung, Mi-Sook; Jeon, Eun-Young; Heo, Yong; Yeo, Kyung-Wook; Jo, Ji-Hoon; Park, Jung Eun; Sohn, Soo Jung; Kim, Tae Sung; Ahn, Il Young; Jeong, Tae-Cheon; Lim, Kyung-Min; Bae, SeungJin

2016-01-01

In order for a novel test method to be applied for regulatory purposes, its reliability and relevance, i.e., reproducibility and predictive capacity, must be demonstrated. Here, we examine the predictive capacity of a novel non-radioisotopic local lymph node assay, LLNA:BrdU-FCM (5-bromo-2'-deoxyuridine-flow cytometry), with a cutoff approach and inferential statistics as a prediction model. 22 reference substances in OECD TG429 were tested with a concurrent positive control, hexylcinnamaldehyde 25%(PC), and the stimulation index (SI) representing the fold increase in lymph node cells over the vehicle control was obtained. The optimal cutoff SI (2.7≤cutoff <3.5), with respect to predictive capacity, was obtained by a receiver operating characteristic curve, which produced 90.9% accuracy for the 22 substances. To address the inter-test variability in responsiveness, SI values standardized with PC were employed to obtain the optimal percentage cutoff (42.6≤cutoff <57.3% of PC), which produced 86.4% accuracy. A test substance may be diagnosed as a sensitizer if a statistically significant increase in SI is elicited. The parametric one-sided t-test and non-parametric Wilcoxon rank-sum test produced 77.3% accuracy. Similarly, a test substance could be defined as a sensitizer if the SI means of the vehicle control, and of the low, middle, and high concentrations were statistically significantly different, which was tested using ANOVA or Kruskal-Wallis, with post hoc analysis, Dunnett, or DSCF (Dwass-Steel-Critchlow-Fligner), respectively, depending on the equal variance test, producing 81.8% accuracy. The absolute SI-based cutoff approach produced the best predictive capacity, however the discordant decisions between prediction models need to be examined further. Copyright © 2015 Elsevier Inc. All rights reserved.

A Simple Test of Class-Level Genetic Association Can Reveal Novel Cardiometabolic Trait Loci.

PubMed

Qian, Jing; Nunez, Sara; Reed, Eric; Reilly, Muredach P; Foulkes, Andrea S

2016-01-01

Characterizing the genetic determinants of complex diseases can be further augmented by incorporating knowledge of underlying structure or classifications of the genome, such as newly developed mappings of protein-coding genes, epigenetic marks, enhancer elements and non-coding RNAs. We apply a simple class-level testing framework, termed Genetic Class Association Testing (GenCAT), to identify protein-coding gene association with 14 cardiometabolic (CMD) related traits across 6 publicly available genome wide association (GWA) meta-analysis data resources. GenCAT uses SNP-level meta-analysis test statistics across all SNPs within a class of elements, as well as the size of the class and its unique correlation structure, to determine if the class is statistically meaningful. The novelty of findings is evaluated through investigation of regional signals. A subset of findings are validated using recently updated, larger meta-analysis resources. A simulation study is presented to characterize overall performance with respect to power, control of family-wise error and computational efficiency. All analysis is performed using the GenCAT package, R version 3.2.1. We demonstrate that class-level testing complements the common first stage minP approach that involves individual SNP-level testing followed by post-hoc ascribing of statistically significant SNPs to genes and loci. GenCAT suggests 54 protein-coding genes at 41 distinct loci for the 13 CMD traits investigated in the discovery analysis, that are beyond the discoveries of minP alone. An additional application to biological pathways demonstrates flexibility in defining genetic classes. We conclude that it would be prudent to include class-level testing as standard practice in GWA analysis. GenCAT, for example, can be used as a simple, complementary and efficient strategy for class-level testing that leverages existing data resources, requires only summary level data in the form of test statistics, and adds significant value with respect to its potential for identifying multiple novel and clinically relevant trait associations.

CorSig: a general framework for estimating statistical significance of correlation and its application to gene co-expression analysis.

PubMed

Wang, Hong-Qiang; Tsai, Chung-Jui

2013-01-01

With the rapid increase of omics data, correlation analysis has become an indispensable tool for inferring meaningful associations from a large number of observations. Pearson correlation coefficient (PCC) and its variants are widely used for such purposes. However, it remains challenging to test whether an observed association is reliable both statistically and biologically. We present here a new method, CorSig, for statistical inference of correlation significance. CorSig is based on a biology-informed null hypothesis, i.e., testing whether the true PCC (ρ) between two variables is statistically larger than a user-specified PCC cutoff (τ), as opposed to the simple null hypothesis of ρ = 0 in existing methods, i.e., testing whether an association can be declared without a threshold. CorSig incorporates Fisher's Z transformation of the observed PCC (r), which facilitates use of standard techniques for p-value computation and multiple testing corrections. We compared CorSig against two methods: one uses a minimum PCC cutoff while the other (Zhu's procedure) controls correlation strength and statistical significance in two discrete steps. CorSig consistently outperformed these methods in various simulation data scenarios by balancing between false positives and false negatives. When tested on real-world Populus microarray data, CorSig effectively identified co-expressed genes in the flavonoid pathway, and discriminated between closely related gene family members for their differential association with flavonoid and lignin pathways. The p-values obtained by CorSig can be used as a stand-alone parameter for stratification of co-expressed genes according to their correlation strength in lieu of an arbitrary cutoff. CorSig requires one single tunable parameter, and can be readily extended to other correlation measures. Thus, CorSig should be useful for a wide range of applications, particularly for network analysis of high-dimensional genomic data. A web server for CorSig is provided at http://202.127.200.1:8080/probeWeb. R code for CorSig is freely available for non-commercial use at http://aspendb.uga.edu/downloads.

A comparison of likelihood ratio tests and Rao's score test for three separable covariance matrix structures.

PubMed

Filipiak, Katarzyna; Klein, Daniel; Roy, Anuradha

2017-01-01

The problem of testing the separability of a covariance matrix against an unstructured variance-covariance matrix is studied in the context of multivariate repeated measures data using Rao's score test (RST). The RST statistic is developed with the first component of the separable structure as a first-order autoregressive (AR(1)) correlation matrix or an unstructured (UN) covariance matrix under the assumption of multivariate normality. It is shown that the distribution of the RST statistic under the null hypothesis of any separability does not depend on the true values of the mean or the unstructured components of the separable structure. A significant advantage of the RST is that it can be performed for small samples, even smaller than the dimension of the data, where the likelihood ratio test (LRT) cannot be used, and it outperforms the standard LRT in a number of contexts. Monte Carlo simulations are then used to study the comparative behavior of the null distribution of the RST statistic, as well as that of the LRT statistic, in terms of sample size considerations, and for the estimation of the empirical percentiles. Our findings are compared with existing results where the first component of the separable structure is a compound symmetry (CS) correlation matrix. It is also shown by simulations that the empirical null distribution of the RST statistic converges faster than the empirical null distribution of the LRT statistic to the limiting χ 2 distribution. The tests are implemented on a real dataset from medical studies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A comparative evaluation of Oratest with the microbiological method of assessing caries activity in children

PubMed Central

Sundaram, Meenakshi; Nayak, Ullal Anand; Ramalingam, Krishnakumar; Reddy, Venugopal; Rao, Arun Prasad; Mathian, Mahesh

2013-01-01

Aims: The aim of this study is to find out whether Oratest can be used as a diagnostic tool in assessing the caries activity by evaluating its relationship to the existing caries status and the salivary streptococcus mutans level. Materials and Methods: The study sample consists of 90 students divided into two groups. Group I (test group) and Group II (control group) consisting of 30 children for control group and 60 children for test group. The sampling of unstimulated saliva for the estimation of streptococcus mutans was done as per the method suggested by Kohler and Bratthall. The plates were then incubated. Rough surface colonies were identified as streptococcus mutans on a pre-determined area of the tip (approximately 1.5 cm2) were counted for each side of spatula pressed against mitis salivarius bacitracin agar using digital colony counter. The results were expressed in colony forming units (CFU). Oratest was carried out in the same patients after the collection of salivary sample for the microbiological method to evaluate the relationship between the two tests. Statistical Analysis Used: The tests used were ANOVA, Pearson Chi-square test, Pearson′s correlation analysis, Mann-Whitney U test and Student′s independent t-test. Results: In the control group and test group, when the streptococcus mutans count (CFU) and Oratest time (minutes) were correlated using Pearson′s correlation analysis, the streptococcus mutans counts was found to be in a statistically significant negative linear relationship with the Oratest time. When the caries status of the children, participated in the test group were correlated with mutans count (CFU) and Oratest time, caries status were found to be in a statistically significant positive linear relationship with streptococcus mutans count and in a significant negative linear relationship with Oratest time. Conclusions: The test proved to be a simple, inexpensive and rapid technique for assessing caries activity since a significant relationship exists clinically with caries status and microbiologically with the streptococcus mutans count of the individual. PMID:23946577

A twelve-year profile of students' SAT scores, GPAs, and MCAT scores from a small university's premedical program.

PubMed

Montague, J R; Frei, J K

1993-04-01

To determine whether significant correlations existed among quantitative and qualitative predictors of students' academic success and quantitative outcomes of such success over a 12-year period in a small university's premedical program. A database was assembled from information on the 199 graduates who earned BS degrees in biology from Barry University's School of Natural and Health Sciences from 1980 through 1991. The quantitative variables were year of BS degree, total score on the Scholastic Aptitude Test (SAT), various measures of undergraduate grade-point averages (GPAs), and total score on the Medical College Admission Test (MCAT); and the qualitative variables were minority (54% of the students) or majority status and transfer (about one-third of the students) or nontransfer status. The statistical methods were multiple analysis of variance and stepwise multiple regression. Statistically significant positive correlations were found among SAT total scores, final GPAs, biology GPAs versus nonbiology GPAs, and MCAT total scores. These correlations held for transfer versus nontransfer students and for minority versus majority students. Over the 12-year period there were significant fluctuations in mean MCAT scores. The students' SAT scores and GPAs proved to be statistically reliable predictors of MCAT scores, but the minority or majority status and the transfer or nontransfer status of the students were statistically insignificant.

The effect of four-phase teaching method on midwifery students’ emotional intelligence in managing the childbirth

PubMed Central

Mohamadirizi, Soheila; Fahami, Fariba; Bahadoran, Parvin; Ehsanpour, Soheila

2015-01-01

Background: An active teaching method has been used widely in medical education. The aim of this study was to determine the effectiveness of the four-phase teaching method on midwifery students’ emotional intelligence (EQ) in managing the childbirth. Materials and Methods: This was an experimental study that performed in 2013 in Isfahan University of Medical Sciences. Thirty midwifery students were involved in this study and selected through a random sampling method. The EQ questionnaire (43Q) was completed by both the groups, before and after the education. The collected data were analyzed using SPSS 14, the independent t-test, and the paired t-test. The statistically significant level was considered to be <0.05. Results: The findings of the independent t-test did not show any significant difference between EQ scores of the experimental and the control group before the intervention, whereas a statistically significant difference was observed after the intervention between the scores of two groups (P = 0.009). The paired t-test showed a statistically significant difference in EQ scores in the two groups after the intervention in the four-phase and the control group, respectively, as P = 0.005 and P = 0.018. Furthermore, the rate of self-efficiency has increased in the experimental group and control group as 66% and 13% (P = 0.024), respectively. Conclusion: The four-phase teaching method can increase the EQ levels of midwifery students. Therefore, the conduction of this educational model is recommended as an effective learning method. PMID:26097861

Feasibility and effects of newly developed balance control trainer for mobility and balance in chronic stroke patients: a randomized controlled trial.

PubMed

Lee, So Hyun; Byun, Seung Deuk; Kim, Chul Hyun; Go, Jin Young; Nam, Hyeon Uk; Huh, Jin Seok; Jung, Tae Du

2012-08-01

To investigate the feasibility and effects of balance training with a newly developed Balance Control Trainer (BCT) that applied the concept of vertical movement for the improvements of mobility and balance in chronic stroke patients. Forty chronic stroke patients were randomly assigned to an experimental or a control group. The experimental group (n=20) underwent training with a BCT for 20 minutes a day, 5 days a week for 4 weeks, in addition to concurrent conventional physical therapy. The control group (n=20) underwent only conventional therapy for 4 weeks. All participants were assessed by: the Functional Ambulation Categories (FAC), 10-meter Walking Test (10mWT), Timed Up and Go test (TUG), Berg Balance Scale (BBS), Korean Modified Barthel Index (MBI), and Manual Muscle Test (MMT) before training, and at 2 and 4 weeks of training. There were statistically significant improvements in all parameters except knee extensor power at 2 weeks of treatment, and in all parameters except MBI which showed further statistically significant progress in the experimental group over the next two weeks (p<0.05). Statistically significant improvements on all measurements were observed in the experimental group after 4 weeks total. Comparing the two groups at 2 and 4 weeks of training respectively, 10mWT, TUG, and BBS showed statistically more significant improvements in the experimental group (p<0.05). Balance training with a newly developed BCT is feasible and may be an effective tool to improve balance and gait in ambulatory chronic stroke patients. Furthermore, it may provide additional benefits when used in conjunction with conventional therapies.

Prevalence of premenstrual syndrome and its relationship to depressive symptoms in first-year university students

PubMed Central

Acikgoz, Ayla; Dayi, Ayfer; Binbay, Tolga

2017-01-01

Objectives: To determine the prevalence of and factors influencing premenstrual syndrome (PMS) in first-year students at a university health campus and to evaluate the relationship between depression and PMS. Methods: This cross-sectional study was conducted on a population of 618 university students from March to June 2016 at Dokuz Eylül University, Izmir, Turkey. Data were collected using the Premenstrual Syndrome Scale (PMSS), Beck Depression Inventory and Student Identification Form. The data were analyzed with Version 20.0 of the Statistical Package for the Social Science. Descriptive statistics, Pearson’s chi-square test, and Chi-square test for trend, and independent samples t test and logistic regression analysis were used. Results: The prevalence of PMS in the university students was 58.1%. Premenstrual syndrome was significantly higher in students who smoked, drink alcohol, and consumed a large amount of fatty and high-calorie foods, in students who had a bad to very bad perception of their economic situation, and those who had any chronic disease or anemia (p<0.05). Premenstrual syndrome was significantly higher in students who had a risk of depression (p<0.01). A statistically significant relationship was determined between the risk of depression and PMSS total score and all PMSS subscale scores except for appetite changes (p<0.01). Conclusion: Premenstrual syndrome was found in more than half of the students who participated in the study. Premenstrual syndrome was higher in students who had a chronic disease and/or an unhealthy lifestyle. There was a statistically significant relationship between PMS and risk of depression. Students who have PMS symptoms should be evaluated for the risk of depression. PMID:29114701

Effect of Different Anti-Oxidants on Shear Bond Strength of Composite Resins to Bleached Human Enamel

PubMed Central

Saladi, Hari Krishna; Bollu, Indira Priyadarshini; Burla, Devipriya; Ballullaya, Srinidhi Vishnu; Devalla, Srihari; Maroli, Sohani; Jayaprakash, Thumu

2015-01-01

Introduction The bond strength of the composite to the bleached enamel plays a very important role in the success and longevity of an aesthetic restoration. Aim The aim of this study was to compare and evaluate the effect of Aloe Vera with 10% Sodium Ascorbate on the Shear bond strength of composite resin to bleached human enamel. Materials and Methods Fifty freshly extracted human maxillary central incisors were selected and divided into 5 groups. Group I and V are unbleached and bleached controls groups respectively. Group II, III, IV served as experimental groups. The labial surfaces of groups II, III, IV, V were treated with 35% Carbamide Peroxide for 30mins. Group II specimens were subjected to delayed composite bonding. Group III and IV specimens were subjected to application of 10% Sodium Ascorbate and leaf extract of Aloe Vera following the Carbamide Peroxide bleaching respectively. Specimens were subjected to shear bond strength using universal testing machine and the results were statistically analysed using ANOVA test. Tukey (HSD) Honest Significant Difference test was used to comparatively analyse statistical differences between the groups. A p-value <0.05 is taken as statistically significant. Results The mean shear bond strength values of Group V showed significantly lower bond strengths than Groups I, II, III, IV (p-value <0.05). There was no statistically significant difference between the shear bond strength values of groups I, II, III, IV. Conclusion Treatment of the bleached enamel surface with Aloe Vera and 10% Sodium Ascorbate provided consistently better bond strength. Aloe Vera may be used as an alternative to 10% Sodium Ascorbate. PMID:26674656

Influence of different iodinated contrast media on the induction of DNA double-strand breaks after in vitro X-ray irradiation.

PubMed

Deinzer, Christoph K W; Danova, Daniela; Kleb, Beate; Klose, Klaus J; Heverhagen, Johannes T

2014-01-01

The objective of this work was to examine differences in DNA double-strand break induction in peripheral blood lymphocytes after in vitro X-ray irradiation between iodinated contrast agents. Four different iodinated X-ray contrast agents--three of them with two different iodine concentrations--and mannitol (negative control; concentration of 150 mg mannitol per ml blood) were pipetted into blood samples so that there was a concentration of 0, 7.5 or 15 mg of iodine per ml blood in the samples. Negative controls without contrast medium (0 mg of iodine per ml blood) were also processed for every irradiation dose. The tubes were exposed to 0, 20 or 500 mGy in vitro X-ray irradiation. After that, the lymphocytes were separated by using density-gradient centrifugation. Fluorescence microscopy was applied to determine the average number of γH2AX-foci per lymphocyte in the presence or absence of different contrast media or mannitol. Differences in the number of γH2AX-foci were statistically analysed by one-way ANOVA and post-hoc Tukey's honestly significant difference test. Iodinated contrast agents led to a statistically significant increase in DNA double-strand breaks after in vitro irradiation. This effect increased statistically significant with rising radiation dose and appeared independent of the contrast agent used (iopromid, iodixanol, iomeprol, iopamidol). A statistically significant difference in DNA damage between the different tested contrast agents was not found. Therefore, the increase in DNA double-strand breaks depends solely on the amount of iodine applied. For evaluation of clinical consequences, our findings could be tested in further animal studies. Copyright © 2014 John Wiley & Sons, Ltd.

An analysis of science versus pseudoscience

NASA Astrophysics Data System (ADS)

Hooten, James T.

2011-12-01

This quantitative study identified distinctive features in archival datasets commissioned by the National Science Foundation (NSF) for Science and Engineering Indicators reports. The dependent variables included education level, and scores for science fact knowledge, science process knowledge, and pseudoscience beliefs. The dependent variables were aggregated into nine NSF-defined geographic regions and examined for the years 2004 and 2006. The variables were also examined over all years available in the dataset. Descriptive statistics were determined and tests for normality and homogeneity of variances were performed using Statistical Package for the Social Sciences. Analysis of Variance was used to test for statistically significant differences between the nine geographic regions for each of the four dependent variables. Statistical significance of 0.05 was used. Tukey post-hoc analysis was used to compute practical significance of differences between regions. Post-hoc power analysis using G*Power was used to calculate the probability of Type II errors. Tests for correlations across all years of the dependent variables were also performed. Pearson's r was used to indicate the strength of the relationship between the dependent variables. Small to medium differences in science literacy and education level were observed between many of the nine U.S. geographic regions. The most significant differences occurred when the West South Central region was compared to the New England and the Pacific regions. Belief in pseudoscience appeared to be distributed evenly across all U.S. geographic regions. Education level was a strong indicator of science literacy regardless of a respondent's region of residence. Recommendations for further study include more in-depth investigation to uncover the nature of the relationship between education level and belief in pseudoscience.

The investigation of the some body parameters of obese and (obese+diabetes) patients with using bioelectrical impedance analysis techniques

NASA Astrophysics Data System (ADS)

Yerlikaya, Emrah; Karageçili, Hasan; Aydin, Ruken Zeynep

2016-04-01

Obesity is a key risk for the development of hyperglycemia, hypertension, hyperlipidemia, insulin resistance and is totally referred to as the metabolic disorders. Diabetes mellitus, a metabolic disorder, is related with hyperglycemia, altered metabolism of lipids, carbohydrates and proteins. The minimum defining characteristic feature to identify diabetes mellitus is chronic and substantiated elevation of circulating glucose concentration. In this study, it is aimed to determine the body composition analyze of obese and (obese+diabetes) patients.We studied the datas taken from three independent groups with the body composition analyzer instrument. The body composition analyzer calculates body parameters, such as body fat ratio, body fat mass, fat free mass, estimated muscle mass, and base metabolic rate on the basis of data obtained by Dual Energy X-ray Absorptiometry using Bioelectrical Impedance Analysis. All patients and healthy subjects applied to Siirt University Medico and their datas were taken. The Statistical Package for Social Sciences version 21 was used for descriptive data analysis. When we compared and analyzed three groups datas, we found statistically significant difference between obese, (obese+diabetes) and control groups values. Anova test and tukey test are used to analyze the difference between groups and to do multiple comparisons. T test is also used to analyze the difference between genders. We observed the statistically significant difference in age and mineral amount p<0.00 between (diabetes+obese) and obese groups. Besides, when these patient groups and control group were analyzed, there were significant difference between most parameters. In terms of education level among the illiterate and university graduates; fat mass kg, fat percentage, internal lubrication, body mass index, water percentage, protein mass percentage, mineral percentage p<0.05, significant statistically difference were observed. This difference especially may result of a sedentary lifestyle.

OPATs: Omnibus P-value association tests.

PubMed

Chen, Chia-Wei; Yang, Hsin-Chou

2017-07-10

Combining statistical significances (P-values) from a set of single-locus association tests in genome-wide association studies is a proof-of-principle method for identifying disease-associated genomic segments, functional genes and biological pathways. We review P-value combinations for genome-wide association studies and introduce an integrated analysis tool, Omnibus P-value Association Tests (OPATs), which provides popular analysis methods of P-value combinations. The software OPATs programmed in R and R graphical user interface features a user-friendly interface. In addition to analysis modules for data quality control and single-locus association tests, OPATs provides three types of set-based association test: window-, gene- and biopathway-based association tests. P-value combinations with or without threshold and rank truncation are provided. The significance of a set-based association test is evaluated by using resampling procedures. Performance of the set-based association tests in OPATs has been evaluated by simulation studies and real data analyses. These set-based association tests help boost the statistical power, alleviate the multiple-testing problem, reduce the impact of genetic heterogeneity, increase the replication efficiency of association tests and facilitate the interpretation of association signals by streamlining the testing procedures and integrating the genetic effects of multiple variants in genomic regions of biological relevance. In summary, P-value combinations facilitate the identification of marker sets associated with disease susceptibility and uncover missing heritability in association studies, thereby establishing a foundation for the genetic dissection of complex diseases and traits. OPATs provides an easy-to-use and statistically powerful analysis tool for P-value combinations. OPATs, examples, and user guide can be downloaded from http://www.stat.sinica.edu.tw/hsinchou/genetics/association/OPATs.htm. © The Author 2017. Published by Oxford University Press.

Analysis of spatial and temporal rainfall trends in Sicily during the 1921-2012 period

NASA Astrophysics Data System (ADS)

Liuzzo, Lorena; Bono, Enrico; Sammartano, Vincenzo; Freni, Gabriele

2016-10-01

Precipitation patterns worldwide are changing under the effects of global warming. The impacts of these changes could dramatically affect the hydrological cycle and, consequently, the availability of water resources. In order to improve the quality and reliability of forecasting models, it is important to analyse historical precipitation data to account for possible future changes. For these reasons, a large number of studies have recently been carried out with the aim of investigating the existence of statistically significant trends in precipitation at different spatial and temporal scales. In this paper, the existence of statistically significant trends in rainfall from observational datasets, which were measured by 245 rain gauges over Sicily (Italy) during the 1921-2012 period, was investigated. Annual, seasonal and monthly time series were examined using the Mann-Kendall non-parametric statistical test to detect statistically significant trends at local and regional scales, and their significance levels were assessed. Prior to the application of the Mann-Kendall test, the historical dataset was completed using a geostatistical spatial interpolation technique, the residual ordinary kriging, and then processed to remove the influence of serial correlation on the test results, applying the procedure of trend-free pre-whitening. Once the trends at each site were identified, the spatial patterns of the detected trends were examined using spatial interpolation techniques. Furthermore, focusing on the 30 years from 1981 to 2012, the trend analysis was repeated with the aim of detecting short-term trends or possible changes in the direction of the trends. Finally, the effect of climate change on the seasonal distribution of rainfall during the year was investigated by analysing the trend in the precipitation concentration index. The application of the Mann-Kendall test to the rainfall data provided evidence of a general decrease in precipitation in Sicily during the 1921-2012 period. Downward trends frequently occurred during the autumn and winter months. However, an increase in total annual precipitation was detected during the period from 1981 to 2012.

Effects of basic character design and animation concepts using the flipped learning and project-based learning approach on learning achievement and creative thinking of higher education students

NASA Astrophysics Data System (ADS)

Autapao, Kanyarat; Minwong, Panthul

2018-01-01

Creative thinking was an important learning skill in the 21st Century via learning and innovation to promote students' creative thinking and working with others and to construct innovation. This is one of the important skills that determine the readiness of the participants to step into the complex society. The purposes of this research were 1) to compare the learning achievement of students after using basic character design and animation concepts using the flipped learning and project-based learning and 2) to make a comparison students' creative thinking between pretest and posttest. The populations were 29 students in Multimedia Technology program at Thepsatri Rajabhat University in the 2nd semester of the academic year 2016. The experimental instruments were lesson plans of basic character design and animation concepts using the flipped learning and project based learning. The data collecting instrument was creative thinking test. The data were analyzed by the arithmetic mean, standard deviation and The Wilcoxon Matched Pairs Signed-Ranks Test. The results of this research were 1) the learning achievement of students were statistically significance of .01 level and 2) the mean score of student's creativity assessment were statistically significance of .05 level. When considering all of 11 KPIs, showed that respondents' post-test mean scores higher than pre-test. And 5 KPIs were statistically significance of .05 level, consist of Originality, Fluency, Elaboration, Resistance to Premature Closure, and Intrinsic Motivation. It's were statistically significance of .042, .004, .049, .024 and .015 respectively. And 6 KPIs were non-statistically significant, include of Flexibility, Tolerance of Ambiguity, Divergent Thinking, Convergent Thinking, Risk Taking, and Extrinsic Motivation. The findings revealed that the flipped learning and project based learning provided students the freedom to simply learn on their own aptitude. When working together with project-based learning, Project based learning focusing on the students' project-based learning construction based on their own interests which allowed the students to increase creative project. This can be applied for other courses in order to plan activities to develop students' work process skills and creative skills. We also recommend that researchers carefully consider the design of lesson plans in accordance with all of 11 KPIs to promote students' creative thinking skills.

Measurements of experimental precision for trials with cowpea (Vigna unguiculata L. Walp.) genotypes.

PubMed

Teodoro, P E; Torres, F E; Santos, A D; Corrêa, A M; Nascimento, M; Barroso, L M A; Ceccon, G

2016-05-09

The aim of this study was to evaluate the suitability of statistics as experimental precision degree measures for trials with cowpea (Vigna unguiculata L. Walp.) genotypes. Cowpea genotype yields were evaluated in 29 trials conducted in Brazil between 2005 and 2012. The genotypes were evaluated with a randomized block design with four replications. Ten statistics that were estimated for each trial were compared using descriptive statistics, Pearson correlations, and path analysis. According to the class limits established, selective accuracy and F-test values for genotype, heritability, and the coefficient of determination adequately estimated the degree of experimental precision. Using these statistics, 86.21% of the trials had adequate experimental precision. Selective accuracy and the F-test values for genotype, heritability, and the coefficient of determination were directly related to each other, and were more suitable than the coefficient of variation and the least significant difference (by the Tukey test) to evaluate experimental precision in trials with cowpea genotypes.

Capture approximations beyond a statistical quantum mechanical method for atom-diatom reactions

NASA Astrophysics Data System (ADS)

Barrios, Lizandra; Rubayo-Soneira, Jesús; González-Lezana, Tomás

2016-03-01

Statistical techniques constitute useful approaches to investigate atom-diatom reactions mediated by insertion dynamics which involves complex-forming mechanisms. Different capture schemes based on energy considerations regarding the specific diatom rovibrational states are suggested to evaluate the corresponding probabilities of formation of such collision species between reactants and products in an attempt to test reliable alternatives for computationally demanding processes. These approximations are tested in combination with a statistical quantum mechanical method for the S + H2(v = 0 ,j = 1) → SH + H and Si + O2(v = 0 ,j = 1) → SiO + O reactions, where this dynamical mechanism plays a significant role, in order to probe their validity.

Tensile strength of laser welded cobalt-chromium alloy with and without an argon atmosphere.

PubMed

Tartari, Anna; Clark, Robert K F; Juszczyk, Andrzej S; Radford, David R

2010-06-01

The tensile strength and depth of weld of two cobalt chromium alloys before and after laser welding with and without an argon gas atmosphere were investigated. Using two cobalt chromium alloys, rod shaped specimens (5 cm x 1.5 mm) were cast. Specimens were sand blasted, sectioned and welded with a pulsed Nd: YAG laser welding machine and tested in tension using an Instron universal testing machine. A statistically significant difference in tensile strength was observed between the two alloys. The tensile strength of specimens following laser welding was significantly less than the unwelded controls. Scanning electron microscopy showed that the micro-structure of the cast alloy was altered in the region of the weld. No statistically significant difference was found between specimens welded with or without an argon atmosphere.

Significant-Loophole-Free Test of Bell's Theorem with Entangled Photons.

PubMed

Giustina, Marissa; Versteegh, Marijn A M; Wengerowsky, Sören; Handsteiner, Johannes; Hochrainer, Armin; Phelan, Kevin; Steinlechner, Fabian; Kofler, Johannes; Larsson, Jan-Åke; Abellán, Carlos; Amaya, Waldimar; Pruneri, Valerio; Mitchell, Morgan W; Beyer, Jörn; Gerrits, Thomas; Lita, Adriana E; Shalm, Lynden K; Nam, Sae Woo; Scheidl, Thomas; Ursin, Rupert; Wittmann, Bernhard; Zeilinger, Anton

2015-12-18

Local realism is the worldview in which physical properties of objects exist independently of measurement and where physical influences cannot travel faster than the speed of light. Bell's theorem states that this worldview is incompatible with the predictions of quantum mechanics, as is expressed in Bell's inequalities. Previous experiments convincingly supported the quantum predictions. Yet, every experiment requires assumptions that provide loopholes for a local realist explanation. Here, we report a Bell test that closes the most significant of these loopholes simultaneously. Using a well-optimized source of entangled photons, rapid setting generation, and highly efficient superconducting detectors, we observe a violation of a Bell inequality with high statistical significance. The purely statistical probability of our results to occur under local realism does not exceed 3.74×10^{-31}, corresponding to an 11.5 standard deviation effect.

Is Cognitive Test-Taking Anxiety Associated With Academic Performance Among Nursing Students?

PubMed

Duty, Susan M; Christian, Ladonna; Loftus, Jocelyn; Zappi, Victoria

2016-01-01

The cognitive component of test anxiety was correlated with academic performance among nursing students. Modest but statistically significant lower examination grade T scores were observed for students with high compared with low levels of cognitive test anxiety (CTA). High levels of CTA were associated with reduced academic performance.

Influence of valproate on language functions in children with epilepsy.

PubMed

Doo, Jin Woong; Kim, Soon Chul; Kim, Sun Jun

2018-01-01

The aim of the current study was to assess the influences of valproate (VPA) on the language functions in newly diagnosed pediatric patients with epilepsy. We reviewed medical records of 53 newly diagnosed patients with epilepsy, who were being treated with VPA monotherapy (n=53; 22 male patients and 31 female patients). The subjects underwent standardized language tests, at least twice, before and after the initiation of VPA. The standardized language tests used were The Test of Language Problem Solving Abilities, a Korean version of The Expressive/Receptive Language Function Test, and the Urimal Test of Articulation and Phonology. Since all the patients analyzed spoke Korean as their first language, we used Korean language tests to reduce the bias within the data. All the language parameters of the Test of Language Problem Solving Abilities slightly improved after the initiation of VPA in the 53 pediatric patients with epilepsy (mean age: 11.6±3.2years), but only "prediction" was statistically significant (determining cause, 14.9±5.1 to 15.5±4.3; making inference, 16.1±5.8 to 16.9±5.6; prediction, 11.1±4.9 to 11.9±4.2; total score of TOPS, 42.0±14.4 to 44.2±12.5). The patients treated with VPA also exhibited a small extension in mean length of utterance in words (MLU-w) when responding, but this was not statistically significant (determining cause, 5.4±2.0 to 5.7±1.6; making inference, 5.8±2.2 to 6.0±1.8; prediction, 5.9±2.5 to 5.9±2.1; total, 5.7±2.1 to 5.9±1.7). The administration of VPA led to a slight, but not statistically significant, improvement in the receptive language function (range: 144.7±41.1 to 148.2±39.7). Finally, there were no statistically significant changes in the percentage of articulation performance after taking VPA. Therefore, our data suggested that VPA did not have negative impact on the language function, but rather slightly improved problem-solving abilities. Copyright © 2017 Elsevier Inc. All rights reserved.

Corneal endothelial cell density and morphology in Phramongkutklao Hospital

PubMed Central

Sopapornamorn, Narumon; Lekskul, Manapon; Panichkul, Suthee

2008-01-01

Objective To describe the corneal endothelial density and morphology in patients of Phramongkutklao Hospital and the relationship between endothelial cell parameters and other factors. Methods Four hundred and four eyes of 202 volunteers were included. Noncontact specular microscopy was performed after taking a history and testing the visual acuity, intraocular pressure measurement, Schirmer’s test and routine eye examination by slit lamp microscope. The studied parameters included mean endothelial cell density (MCD), coefficient of variation (CV), and percentage of hexagonality. Results The mean age of volunteers was 45.73 years; the range being 20 to 80 years old. Their MCD (SD), mean percentage of CV (SD) and mean (SD) percentage of hexagonality were 2623.49(325) cell/mm2, 39.43(8.23)% and 51.50(10.99)%, respectively. Statistically, MCD decreased significantly with age (p < 0.01). There was a significant difference in the percentage of CV between genders. There was no statistical significance between parameters and other factors. Conclusion The normative data of the corneal endothelium of Thai eyes indicated that, statistically, MCD decreased significantly with age. Previous studies have reported no difference in MCD, percentage of CV, and percentage of hexagonality between gender. Nevertheless, significantly different percentages of CV between genders were presented in this study. PMID:19668398

Harnessing Multivariate Statistics for Ellipsoidal Data in Structural Geology

NASA Astrophysics Data System (ADS)

Roberts, N.; Davis, J. R.; Titus, S.; Tikoff, B.

2015-12-01

Most structural geology articles do not state significance levels, report confidence intervals, or perform regressions to find trends. This is, in part, because structural data tend to include directions, orientations, ellipsoids, and tensors, which are not treatable by elementary statistics. We describe a full procedural methodology for the statistical treatment of ellipsoidal data. We use a reconstructed dataset of deformed ooids in Maryland from Cloos (1947) to illustrate the process. Normalized ellipsoids have five degrees of freedom and can be represented by a second order tensor. This tensor can be permuted into a five dimensional vector that belongs to a vector space and can be treated with standard multivariate statistics. Cloos made several claims about the distribution of deformation in the South Mountain fold, Maryland, and we reexamine two particular claims using hypothesis testing: 1) octahedral shear strain increases towards the axial plane of the fold; 2) finite strain orientation varies systematically along the trend of the axial trace as it bends with the Appalachian orogen. We then test the null hypothesis that the southern segment of South Mountain is the same as the northern segment. This test illustrates the application of ellipsoidal statistics, which combine both orientation and shape. We report confidence intervals for each test, and graphically display our results with novel plots. This poster illustrates the importance of statistics in structural geology, especially when working with noisy or small datasets.

TREAT (TREe-based Association Test)

Cancer.gov

TREAT is an R package for detecting complex joint effects in case-control studies. The test statistic is derived from a tree-structure model by recursive partitioning the data. Ultra-fast algorithm is designed to evaluate the significance of association between candidate gene and disease outcome

Effects of animal-assisted therapy on agitated behaviors and social interactions of older adults with dementia.

PubMed

Richeson, Nancy E

2003-01-01

The effects of a therapeutic recreation intervention using animal-assisted therapy (AAT) on the agitated behaviors and social interactions of older adults with dementia were examined using the Cohen-Mansfield Agitation Inventory and the Animal-Assisted Therapy Flow Sheet. In a pilot study, 15 nursing home residents with dementia participated in a daily AAT intervention for three weeks. Results showed statistically significant decreases in agitated behaviors and a statistically significant increase in social interaction pretest to post-test.

Effects of Long-Term Thermal Exposure on Commercially Pure Titanium Grade 2 Elevated-Temperature Tensile Properties

NASA Technical Reports Server (NTRS)

Ellis, David L.

2012-01-01

Elevated-temperature tensile testing of commercially pure titanium (CP Ti) Grade 2 was conducted for as-received commercially produced sheet and following thermal exposure at 550 and 650 K (531 and 711 F) for times up to 5000 h. The tensile testing revealed some statistical differences between the 11 thermal treatments, but most thermal treatments were statistically equivalent. Previous data from room temperature tensile testing was combined with the new data to allow regression and development of mathematical models relating tensile properties to temperature and thermal exposure. The results indicate that thermal exposure temperature has a very small effect, whereas the thermal exposure duration has no statistically significant effects on the tensile properties. These results indicate that CP Ti Grade 2 will be thermally stable and suitable for long-duration space missions.

What's in a Teacher Test? Assessing the Relationship between Teacher Test Scores and Student Secondary STEM Achievement. CEDR Working Paper. WP #2016-4

ERIC Educational Resources Information Center

Goldhaber, Dan; Gratz, Trevor; Theobald, Roddy

2016-01-01

We investigate the predictive validity of teacher credential test scores for student performance in secondary STEM classrooms in Washington state. After replicating earlier findings that teacher basic skills licensure test scores are a modest and statistically significant predictor of student math test score gains in elementary grades, we focus on…

Post-Graduate Student Performance in "Supervised In-Class" vs. "Unsupervised Online" Multiple Choice Tests: Implications for Cheating and Test Security

ERIC Educational Resources Information Center

Ladyshewsky, Richard K.

2015-01-01

This research explores differences in multiple choice test (MCT) scores in a cohort of post-graduate students enrolled in a management and leadership course. A total of 250 students completed the MCT in either a supervised in-class paper and pencil test or an unsupervised online test. The only statistically significant difference between the nine…

Critical analysis of adsorption data statistically

NASA Astrophysics Data System (ADS)

Kaushal, Achla; Singh, S. K.

2017-10-01

Experimental data can be presented, computed, and critically analysed in a different way using statistics. A variety of statistical tests are used to make decisions about the significance and validity of the experimental data. In the present study, adsorption was carried out to remove zinc ions from contaminated aqueous solution using mango leaf powder. The experimental data was analysed statistically by hypothesis testing applying t test, paired t test and Chi-square test to (a) test the optimum value of the process pH, (b) verify the success of experiment and (c) study the effect of adsorbent dose in zinc ion removal from aqueous solutions. Comparison of calculated and tabulated values of t and χ 2 showed the results in favour of the data collected from the experiment and this has been shown on probability charts. K value for Langmuir isotherm was 0.8582 and m value for Freundlich adsorption isotherm obtained was 0.725, both are <1, indicating favourable isotherms. Karl Pearson's correlation coefficient values for Langmuir and Freundlich adsorption isotherms were obtained as 0.99 and 0.95 respectively, which show higher degree of correlation between the variables. This validates the data obtained for adsorption of zinc ions from the contaminated aqueous solution with the help of mango leaf powder.

A close examination of double filtering with fold change and t test in microarray analysis

PubMed Central

2009-01-01

Background Many researchers use the double filtering procedure with fold change and t test to identify differentially expressed genes, in the hope that the double filtering will provide extra confidence in the results. Due to its simplicity, the double filtering procedure has been popular with applied researchers despite the development of more sophisticated methods. Results This paper, for the first time to our knowledge, provides theoretical insight on the drawback of the double filtering procedure. We show that fold change assumes all genes to have a common variance while t statistic assumes gene-specific variances. The two statistics are based on contradicting assumptions. Under the assumption that gene variances arise from a mixture of a common variance and gene-specific variances, we develop the theoretically most powerful likelihood ratio test statistic. We further demonstrate that the posterior inference based on a Bayesian mixture model and the widely used significance analysis of microarrays (SAM) statistic are better approximations to the likelihood ratio test than the double filtering procedure. Conclusion We demonstrate through hypothesis testing theory, simulation studies and real data examples, that well constructed shrinkage testing methods, which can be united under the mixture gene variance assumption, can considerably outperform the double filtering procedure. PMID:19995439

Minor salivary glands and labial mucous membrane graft in the treatment of severe symblepharon and dry eye in patients with Stevens-Johnson syndrome.

PubMed

Sant' Anna, Ana Estela B P P; Hazarbassanov, Rossen M; de Freitas, Denise; Gomes, José Álvaro P

2012-02-01

To evaluate minor salivary glands and labial mucous membrane graft in patients with severe symblepharon and dry eye secondary to Stevens-Johnson syndrome (SJS). A prospective, non-comparative, interventional case series of 19 patients with severe symblepharon and dry eye secondary to SJS who underwent labial mucous membrane and minor salivary glands transplantation. A complete ophthalmic examination including the Schirmer I test was performed prior to and following surgery. All patients had a preoperative Schirmer I test value of zero. Nineteen patients with severe symblepharon and dry eye secondary to SJS were included in the study. There was a statistically significant improvement in the best spectacle-corrected visual acuity in eight patients (t test; p=0.0070). Values obtained in the Schirmer I test improved significantly in 14 eyes (73.7%) 6 months following surgery (χ(2) test; p=0.0094). A statistically significant increase in tear production (Schirmer I test) was found in eyes that received more than 10 glands per graft compared with eyes that received fewer glands (χ(2) test; p=0.0096). Corneal transparency improved significantly in 11 (72.2%) eyes and corneal neovascularisation improved significantly in five eyes (29.4%) (McNemar test; p=0.001 and p=0.0005). The symptoms questionnaire revealed improvement in foreign body sensation in 53.6% of the patients, in photophobia in 50.2% and in pain in 54.8% (Kruskal-Wallis test; p=0.0167). Labial mucous membrane and minor salivary glands transplantation were found to constitute a good option for the treatment of severe symblepharon and dry eye secondary to SJS. This may be considered as a step prior to limbal stem cell and corneal transplantation in these patients.

Prevalence of orthorexia nervosa in resident medical doctors in the faculty of medicine (Ankara, Turkey).

PubMed

Bağci Bosi, A Tülay; Camur, Derya; Güler, Cağatay

2007-11-01

This study has been carried out to "identify highly sensitive behavior on healthy nutrition (orthorexia nervosa-ON)" in residence medical doctors (MD) in the Faculty of Medicine. Diagnoses of ON was based on the presence of a disorder with obsessive-compulsive personality. The study is a cross-sectional research, which reached out to the entire 318 MD. The ORTO-15 test was used to propose a diagnostic proceeding and to try verify the prevalence of ON. Those subjects who were classified below 40 from the ORTO-15 test are accepted to have ON. Chi-square test, ANOVA (univariate) analysis and logistic regression were used for analyses of the data. Mean score of the participants from the ORTO-15 test is 39.8+/-0.22, and there is no statistical difference between women and men. A total of 45.5% of the residence MD involved in the research scored below 40 in the ORTO-15 test. Those who do their food shopping themselves, skip a meal with a salad/fruit, care about the quality of the things they eat, think that eating outside is healthy, look at the content of what they eat and the content of food is important in selection of a product score lower in their average marks in ORTO-15 and the difference among the groups is statistically significant. Food selection of 20.1% of the male participants and 38.9% of the female participants among the residence MD is influenced by the programs on nutrition/health in mass-media. The difference between the groups is statistically significant (p<0.05). Female medical doctors are more careful than men of their physical appearance and weight control and consume less caloric food, which is statistically significant. Since those who exhibit "healthy fanatic" eating habits may have a risk of ON in the future, it would be useful to conduct studies that identify the prevalence of ON in the public.

Test Vehicle Forebody Wake Effects on CPAS Parachutes

NASA Technical Reports Server (NTRS)

Ray, Eric S.

2017-01-01

Parachute drag performance has been reconstructed for a large number of Capsule Parachute Assembly System (CPAS) flight tests. This allows for determining forebody wake effects indirectly through statistical means. When data are available in a "clean" wake, such as behind a slender test vehicle, the relative degradation in performance for other test vehicles can be computed as a Pressure Recovery Fraction (PRF). All four CPAS parachute types were evaluated: Forward Bay Cover Parachutes (FBCPs), Drogues, Pilots, and Mains. Many tests used the missile-shaped Parachute Compartment Drop Test Vehicle (PCDTV) to obtain data at high airspeeds. Other tests used the Orion "boilerplate" Parachute Test Vehicle (PTV) to evaluate parachute performance in a representative heatshield wake. Drag data from both vehicles are normalized to a "capsule" forebody equivalent for Orion simulations. A separate database of PCDTV-specific performance is maintained to accurately predict flight tests. Data are shared among analogous parachutes whenever possible to maximize statistical significance.

Effects of suvorexant, an orexin receptor antagonist, on sleep parameters as measured by polysomnography in healthy men.

PubMed

Sun, Hong; Kennedy, William P; Wilbraham, Darren; Lewis, Nicole; Calder, Nicole; Li, Xiaodong; Ma, Junshui; Yee, Ka Lai; Ermlich, Susan; Mangin, Eric; Lines, Christopher; Rosen, Laura; Chodakewitz, Jeffrey; Murphy, Gail M

2013-02-01

Suvorexant (MK-4305) is an orexin receptor antagonist being developed for the treatment of insomnia. This report describes the effects of nighttime administration of suvorexant on polysomnography (PSG) sleep parameters in healthy young men. Randomized, double-blind, placebo-controlled, 4-period crossover PSG study, followed by an additional 5(th) period to assess pharmacokinetics. Sleep laboratory. Healthy young men between 18 and 45 years of age (22 enrolled, 19 completed). Periods 1-4: suvorexant (10 mg, 50 mg, or 100 mg) or placebo 1 h before nighttime PSG recording. Period 5: suvorexant 10 mg, 50 mg, or 100 mg. In Periods 1-4, overnight sleep parameters were recorded by PSG and next-morning residual effects were assessed by psychomotor performance tests and subjective assessments. Statistically significant sleep-promoting effects were observed with all doses of suvorexant compared to placebo. Suvorexant 50 mg and 100 mg significantly decreased latency to persistent sleep and wake after sleep onset time, and increased sleep efficiency. Suvorexant 10 mg significantly decreased wake after sleep onset time. There were no statistically significant effects of suvorexant on EEG frequency bands including delta (slow wave) activity based on power spectral analysis. Suvorexant was well tolerated. There was no evidence of next-day residual effects for suvorexant 10 mg. Suvorexant 50 mg statistically significantly reduced subjective alertness, and suvorexant 100 mg significantly increased reaction time and reduced subjective alertness. There were no statistically significant effects of any suvorexant dose on digit symbol substitution test performance. In Period 5, plasma samples of suvorexant were collected for pharmacokinetic evaluation. The median T(max) was 3 hours and apparent terminal t(½) was 9-13 hours. In healthy young men without sleep disorders, suvorexant promoted sleep with some evidence of residual effects at the highest doses.

The Antinociceptive Effects of Hydroalcoholic Extract of Borago Officinalis Flower in Male Rats Using Formalin Test.

PubMed

Shahraki, Mohammad Reza; Ahmadimoghadm, Mahdieh; Shahraki, Ahmad Reza

2015-10-01

Borago officinalis flower (borage) is a known sedative in herbal medicine; the aim of the present study was to evaluate the antinociceptive effect of borage hydroalcoholic extract in formalin test male rats. Fifty-six adult male albino Wistar rats were randomly divided into seven groups: Control groups of A (intact), B (saline), and C (Positive control) plus test groups of D, E, F, and G (n=8). The groups D, E, and F received 6.25, 12.5, and 25 mg/kg, Borago officinalis flower hydroalcholic extract before the test, respectively but group G received 25 mg/kg borage extract and aspirin before the test. A biphasic pain was induced by injection of formalin 1%. The obtained data were analyzed by SPSS software ver. 17 employing statistical tests of Kruskal-Wallis and Mann-Whitney. The results were expressed as mean±SD. Statistical differences were considered significant at P<0.05. The results revealed that the acute and chronic pain behavior score in test groups of D, E, F, and G significantly decreased compared to groups A and B, but this score did not show any difference compared to group C. Moreover, chronic pain behavior score in group G was significantly lower than all other groups. The results indicated that Borago officinalis hydroalcoholic extract affects the acute and chronic pain behavior response in formaline test male rats.

Accuracy Evaluation of the Unified P-Value from Combining Correlated P-Values

PubMed Central

Alves, Gelio; Yu, Yi-Kuo

2014-01-01

Meta-analysis methods that combine -values into a single unified -value are frequently employed to improve confidence in hypothesis testing. An assumption made by most meta-analysis methods is that the -values to be combined are independent, which may not always be true. To investigate the accuracy of the unified -value from combining correlated -values, we have evaluated a family of statistical methods that combine: independent, weighted independent, correlated, and weighted correlated -values. Statistical accuracy evaluation by combining simulated correlated -values showed that correlation among -values can have a significant effect on the accuracy of the combined -value obtained. Among the statistical methods evaluated those that weight -values compute more accurate combined -values than those that do not. Also, statistical methods that utilize the correlation information have the best performance, producing significantly more accurate combined -values. In our study we have demonstrated that statistical methods that combine -values based on the assumption of independence can produce inaccurate -values when combining correlated -values, even when the -values are only weakly correlated. Therefore, to prevent from drawing false conclusions during hypothesis testing, our study advises caution be used when interpreting the -value obtained from combining -values of unknown correlation. However, when the correlation information is available, the weighting-capable statistical method, first introduced by Brown and recently modified by Hou, seems to perform the best amongst the methods investigated. PMID:24663491

A Comparative Study on the Role of Xpert MTB/RIF in Testing Different Types of Spinal Tuberculosis Tissue Specimens.

PubMed

Tang, Liang; Feng, Shiqing; Gao, Ruixiao; Han, Chenfu; Sun, Xiaochen; Bao, Yucheng; Zhang, Wenlong

2017-12-01

The aim of the present study was to compare the efficacy of the commercial Xpert Mycobacterium tuberculosis/rifampin (MTB/RIF) test for evaluating different types of spinal tuberculosis (TB) tissue specimens. Pus, granulation tissue, and caseous necrotic tissue specimens from 223 patients who were diagnosed with spinal TB and who underwent curettage were collected for bacterial culture and the Xpert MTB/RIF assay to calculate the positive rate. Bacterial culture and phenotypic drug sensitivity testing (pDST) were adopted as the gold standards to calculate the sensitivity and specificity of the Xpert bacterial detection and drug resistance (DR) test. The positive rate (68.61% ± 7.35%) from the Xpert MTB/RIF assays of spinal TB patients' tissue specimens was higher compared with bacterial culture (44.39% ± 6.51%, Z = 5.1642, p < 0.01), and the positive rates from Xpert MTB/RIF assays on the three types of specimens were all higher than those of bacterial culture, with statistically significant results for pus and granulation tissue specimens. The positive rates for pus using the two bacteriological tests were higher than those for granulation tissue but were not statistically significant. However, the positive rates obtained from granulation tissue were statistically significantly higher than those obtained from caseous necrotic tissue. With bacterial culture and pDST as the gold standards, the sensitivity of Xpert MTB/RIF assays for MTB was 96.97%, while the sensitivity and specificity of the DR test also remained relatively high. For efficient and accurate diagnosis of spinal TB and DR and timely provision of effective treatment, multiple specimens, especially the pus of spinal TB patients, should be collected for Xpert MTB/RIF assays.

The "1-3-5 cough test": comparing the severity of urodynamic stress incontinence with severity measures of subjective perception of stress urinary incontinence.

PubMed

Grigoriadis, Themos; Giannoulis, George; Zacharakis, Dimitris; Protopapas, Athanasios; Cardozo, Linda; Athanasiou, Stavros

2016-03-01

The purpose of the study was to examine whether a test performed during urodynamics, the "1-3-5 cough test", could determine the severity of urodynamic stress incontinence (USI). We included women referred for urodynamics who were diagnosed with USI. The "1-3-5 cough test" was performed to grade the severity of USI at the completion of filling cystometry. A diagnosis of "severe", "moderate" or "mild" USI was given if urine leakage was observed after one, three or five consecutive coughs respectively. We examined the associations between grades of USI severity and measures of subjective perception of stress urinary incontinence (SUI): International Consultation of Incontinence Modular Questionnaire-Female Lower Urinary Tract Symptom (ICIQ-FLUTS), King's Health Questionnaire (KHQ), Urinary Distress Inventory-6 (UDI-6), Urinary Impact Questionnaire-7 (UIQ-7). A total of 1,181 patients completed the ICIQ-FLUTS and KHQ and 612 completed the UDI-6 and UIQ-7 questionnaires. There was a statistically significant association of higher grades of USI severity with higher scores of the incontinence domain of the ICIQ-FLUTS. The scores of the UDI-6, UIQ-7 and of all KHQ domains (with the exception of general health perception and personal relationships) had statistically significant larger mean values for higher USI severity grade. Groups of higher USI severity had statistically significant associations with higher scores of most of the subjective measures of SUI. Severity of USI, as defined by the "1-3-5 cough test", was associated with the severity of subjective measures of SUI. This test may be a useful tool for the objective interpretation of patients with SUI who undergo urodynamics.

Correlation of MRI Visual Scales with Neuropsychological Profile in Mild Cognitive Impairment of Parkinson's Disease.

PubMed

Vasconcellos, Luiz Felipe; Pereira, João Santos; Adachi, Marcelo; Greca, Denise; Cruz, Manuela; Malak, Ana Lara; Charchat-Fichman, Helenice; Spitz, Mariana

2017-01-01

Few studies have evaluated magnetic resonance imaging (MRI) visual scales in Parkinson's disease-Mild Cognitive Impairment (PD-MCI). We selected 79 PD patients and 92 controls (CO) to perform neurologic and neuropsychological evaluation. Brain MRI was performed to evaluate the following scales: Global Cortical Atrophy (GCA), Fazekas, and medial temporal atrophy (MTA). The analysis revealed that both PD groups (amnestic and nonamnestic) showed worse performance on several tests when compared to CO. Memory, executive function, and attention impairment were more severe in amnestic PD-MCI group. Overall analysis of frequency of MRI visual scales by MCI subtype did not reveal any statistically significant result. Statistically significant inverse correlation was observed between GCA scale and Mini-Mental Status Examination (MMSE), Montreal Cognitive Assessment (MoCA), semantic verbal fluency, Stroop test, figure memory test, trail making test (TMT) B, and Rey Auditory Verbal Learning Test (RAVLT). The MTA scale correlated with Stroop test and Fazekas scale with figure memory test, digit span, and Stroop test according to the subgroup evaluated. Visual scales by MRI in MCI should be evaluated by cognitive domain and might be more useful in more severely impaired MCI or dementia patients.

What can we learn from noise? — Mesoscopic nonequilibrium statistical physics —

PubMed Central

KOBAYASHI, Kensuke

2016-01-01

Mesoscopic systems — small electric circuits working in quantum regime — offer us a unique experimental stage to explorer quantum transport in a tunable and precise way. The purpose of this Review is to show how they can contribute to statistical physics. We introduce the significance of fluctuation, or equivalently noise, as noise measurement enables us to address the fundamental aspects of a physical system. The significance of the fluctuation theorem (FT) in statistical physics is noted. We explain what information can be deduced from the current noise measurement in mesoscopic systems. As an important application of the noise measurement to statistical physics, we describe our experimental work on the current and current noise in an electron interferometer, which is the first experimental test of FT in quantum regime. Our attempt will shed new light in the research field of mesoscopic quantum statistical physics. PMID:27477456

What can we learn from noise? - Mesoscopic nonequilibrium statistical physics.

PubMed

Kobayashi, Kensuke

2016-01-01

Mesoscopic systems - small electric circuits working in quantum regime - offer us a unique experimental stage to explorer quantum transport in a tunable and precise way. The purpose of this Review is to show how they can contribute to statistical physics. We introduce the significance of fluctuation, or equivalently noise, as noise measurement enables us to address the fundamental aspects of a physical system. The significance of the fluctuation theorem (FT) in statistical physics is noted. We explain what information can be deduced from the current noise measurement in mesoscopic systems. As an important application of the noise measurement to statistical physics, we describe our experimental work on the current and current noise in an electron interferometer, which is the first experimental test of FT in quantum regime. Our attempt will shed new light in the research field of mesoscopic quantum statistical physics.

Finding P-Values for F Tests of Hypothesis on a Spreadsheet.

ERIC Educational Resources Information Center

Rochowicz, John A., Jr.

The calculation of the F statistic for a one-factor analysis of variance (ANOVA) and the construction of an ANOVA tables are easily implemented on a spreadsheet. This paper describes how to compute the p-value (observed significance level) for a particular F statistic on a spreadsheet. Decision making on a spreadsheet and applications to the…

Hydrogeology and water quality of glacial-drift aquifers in the Bemidji-Bagley area, Beltrami, Clearwater, Cass, and Hubbard counties, Minnesota

USGS Publications Warehouse

Stark, J.R.; Busch, J.P.; Deters, M.H.

1991-01-01

The Kruskil-Wallis test, a nonparametric that for 12 of the 21 constituents sampled in groups in the unconfined-drift aquifer, a of these constituents and land use was found statistical technique, indicated common in all land-use type relation between the concentration to be statistically significant.

Effects of metacognitive instruction on the academic achievement of students in the secondary sciences

NASA Astrophysics Data System (ADS)

Bianchi, Gregory A.

The purpose of this study was to investigate the effects of reflective assessment in the form of situated metacognitive prompts on student achievement in the secondary sciences. A second goal was to determine whether specific gender differences existed in terms of student responsiveness to the metacognitive interventions. Participants in the study consisted of a convenience sample from a population of ninth-grade honors biology students in a large suburban school district located near Seattle, Washington. Beyond answering the specific research questions raised in this study, an additional aim was to broaden the growing body of research pertaining to the effect of metacognition on student achievement. A quasi-experimental, non-equivalent control group design was employed in this study. Descriptive and inferential statistics were computed to address the specific research questions raised. Specifically, a three-way repeated-measures ANOVA was performed. For this purpose, a single within-subjects factor, termed Testing, was defined. Three levels were allocated to this factor, and quantitative data from the Pretest, Posttest, and Retention Test were assigned to the levels, respectively. Group and Gender were defined as between-subjects factors, and both were allocated two levels; the two Group levels were Reflective and Non-Reflective. The effects of Group and Gender on each of the three quantitative measures were examined singly and in interaction with each other. Tests of statistical significance were analyzed at the .05 level. There was a statistically significant effect for Group (Reflective, Non-Reflective) by Testing (Pretest, Posttest, Retention Test). A three-way repeated-measures ANOVA procedure revealed that students in the Reflective group outperformed students in the Non-Reflective group (F = 10.258, p = .002, Partial eta 2 = .088). According to the effect size estimate, almost 9% of variance in the Testing variable was attributable to the Group variable. There was not a significant interaction effect for Gender. A three-way repeated-measures ANOVA procedure revealed that Testing X Group X Gender did not yield a statistically significant F ratio (F = 1.471, p = .228, Partial eta2 = .014). Students in the Reflective group outperformed students in the Non-Reflective group, regardless of gender. The findings of this study offer modest evidence that reflective assessment in the form of situated metacognitive prompts may improve student academic outcomes at the secondary level. This study failed to provide a significant finding regarding gender-related variation in a metacognitive learning cycle.

A time to be born: Variation in the hour of birth in a rural population of Northern Argentina.

PubMed

Chaney, Carlye; Goetz, Laura G; Valeggia, Claudia

2018-04-17

The present study aimed at investigating the timing of birth across the day in a rural population of indigenous and nonindigenous women in the province of Formosa, Argentina in order to explore the variation in patterns in a non-Western setting. This study utilized birth record data transcribed from delivery room records at a rural hospital in the province of Formosa, northern Argentina. The sample included data for Criollo, Wichí, and Toba/Qom women (n = 2421). Statistical analysis was conducted using directional statistics to identify a mean sample direction. Chi-square tests for homogeneity were also used to test for statistical significant differences between hours of the day. The mean sample direction was 81.04°, which equates to 5:24 AM when calculated as time on a 24-hr clock. Chi-squared analyses showed a statistically significant peak in births between 12:00 and 4:00 AM. Birth counts generally declined throughout the day until a statistically significant trough around 5:00 PM. This pattern may be associated with the circadian rhythms of hormone release, particularly melatonin, on a proximate level. At the ultimate level, giving birth in the early hours of the morning may have been selected to time births when the mother could benefit from the predator protection and support provided by her social group as well as increased mother-infant bonding from a more peaceful environment. © 2018 Wiley Periodicals, Inc.

Intrabolus pressure on high-resolution manometry distinguishes fibrostenotic and inflammatory phenotypes of eosinophilic esophagitis.

PubMed

Colizzo, J M; Clayton, S B; Richter, J E

2016-08-01

The aim of this investigation was to determine the motility patterns of inflammatory and fibrostenotic phenotypes of eosinophilic esophagitis (EoE) utilizing high-resolution manometry (HRM). Twenty-nine patients with a confirmed diagnosis of EoE according to clinicopathological criteria currently being managed at the Joy McCann Culverhouse Swallowing Center at the University of South Florida were included in the retrospective analysis. Only patients who completed HRM studies were included in the analysis. Patients were classified into inflammatory or fibrostenotic subtypes based on baseline endoscopic evidence. Their baseline HRM studies prior to therapy were analyzed. Manometric data including distal contractile integral, integrated relaxation pressure, and intrabolus pressure (IBP) values were recorded. HRM results were interpreted according to the Chicago Classification system. Statistical analysis was performed with SPSS software (Version 22, IBM Co., Armonk, NY, USA). Data were compared utilizing Student's t-test, χ(2) test, Pearson correlation, and Spearman correlation tests. Statistical significance was set at P < 0.05. A total of 29 patients with EoE were included into the retrospective analysis. The overall average age among patients was 40 years. Male patients comprised 62% of the overall population. Both groups were similar in age, gender, and overall clinical presentation. Seventeen patients (58%) had fibrostenotic disease, and 12 (42%) displayed inflammatory disease. The average IBP for the fibrostenotic and inflammatory groups were 18.6 ± 6.0 mmHg and 12.6 ± 3.5 mmHg, respectively (P < 0.05). Strictures were only seen in the fibrostenotic group. Of the fibrostenotic group, 6 (35%) demonstrated proximal esophageal strictures, 7 (41%) had distal strictures, 3 (18%) had mid-esophageal strictures, and 1 (6%) patient had pan-esophageal strictures. There was no statistically significant correlation between the level of esophageal stricture and degree of IBP. Integrated relaxation pressure, distal contractile integral, and other HRM metrics did not demonstrate statistical significance between the two subtypes. There also appeared no statistically significant correlation between patient demographics and esophageal metrics. Patients with the fibrostenotic phenotype of EoE demonstrated an IBP that was significantly higher than that of the inflammatory group. © 2015 International Society for Diseases of the Esophagus.

Three-dimensional volume-rendering technique in the angiographic follow-up of intracranial aneurysms embolized with coils.

PubMed

Zhou, Bing; Li, Ming-Hua; Wang, Wu; Xu, Hao-Wen; Cheng, Yong-De; Wang, Jue

2010-03-01

The authors conducted a study to evaluate the advantages of a 3D volume-rendering technique (VRT) in follow-up digital subtraction (DS) angiography of coil-embolized intracranial aneurysms. One hundred nine patients with 121 intracranial aneurysms underwent endovascular coil embolization and at least 1 follow-up DS angiography session at the authors' institution. Two neuroradiologists independently evaluated the conventional 2D DS angiograms, rotational angiograms, and 3D VRT images obtained at the interventional procedures and DS angiography follow-up. If multiple follow-up sessions were performed, the final follow-up was mainly considered. The authors compared the 3 techniques for their ability to detect aneurysm remnants (including aneurysm neck and sac remnants) and parent artery stenosis based on the angiographic follow-up. The Kruskal-Wallis test was used for group comparisons, and the kappa test was used to measure interobserver agreement. Statistical analyses were performed using commercially available software. There was a high statistical significance among 2D DS angiography, rotational angiography, and 3D VRT results (X(2) = 9.9613, p = 0.0069) when detecting an aneurysm remnant. Further comparisons disclosed a statistical significance between 3D VRT and rotational angiography (X(2) = 4.9754, p = 0.0257); a high statistical significance between 3D VRT and 2D DS angiography (X(2) = 8.9169, p = 0.0028); and no significant difference between rotational angiography and 2D DS angiography (X(2) = 0.5648, p = 0.4523). There was no statistical significance among the 3 techniques when detecting parent artery stenosis (X(2) = 2.5164, p = 0.2842). One case, in which parent artery stenosis was diagnosed by 2D DS angiography and rotational angiography, was excluded by 3D VRT following observations of multiple views. The kappa test showed good agreement between the 2 observers. The 3D VRT is more sensitive in detecting aneurysm remnants than 2D DS angiography and rotational angiography and is helpful for identifying parent artery stenosis. The authors recommend this technique for the angiographic follow-up of patients with coil-embolized aneurysms.

Filtering genetic variants and placing informative priors based on putative biological function.

PubMed

Friedrichs, Stefanie; Malzahn, Dörthe; Pugh, Elizabeth W; Almeida, Marcio; Liu, Xiao Qing; Bailey, Julia N

2016-02-03

High-density genetic marker data, especially sequence data, imply an immense multiple testing burden. This can be ameliorated by filtering genetic variants, exploiting or accounting for correlations between variants, jointly testing variants, and by incorporating informative priors. Priors can be based on biological knowledge or predicted variant function, or even be used to integrate gene expression or other omics data. Based on Genetic Analysis Workshop (GAW) 19 data, this article discusses diversity and usefulness of functional variant scores provided, for example, by PolyPhen2, SIFT, or RegulomeDB annotations. Incorporating functional scores into variant filters or weights and adjusting the significance level for correlations between variants yielded significant associations with blood pressure traits in a large family study of Mexican Americans (GAW19 data set). Marker rs218966 in gene PHF14 and rs9836027 in MAP4 significantly associated with hypertension; additionally, rare variants in SNUPN significantly associated with systolic blood pressure. Variant weights strongly influenced the power of kernel methods and burden tests. Apart from variant weights in test statistics, prior weights may also be used when combining test statistics or to informatively weight p values while controlling false discovery rate (FDR). Indeed, power improved when gene expression data for FDR-controlled informative weighting of association test p values of genes was used. Finally, approaches exploiting variant correlations included identity-by-descent mapping and the optimal strategy for joint testing rare and common variants, which was observed to depend on linkage disequilibrium structure.

Dental enamel defect diagnosis through different technology-based devices.

PubMed

Kobayashi, Tatiana Yuriko; Vitor, Luciana Lourenço Ribeiro; Carrara, Cleide Felício Carvalho; Silva, Thiago Cruvinel; Rios, Daniela; Machado, Maria Aparecida Andrade Moreira; Oliveira, Thais Marchini

2018-06-01

Dental enamel defects (DEDs) are faulty or deficient enamel formations of primary and permanent teeth. Changes during tooth development result in hypoplasia (a quantitative defect) and/or hypomineralisation (a qualitative defect). To compare technology-based diagnostic methods for detecting DEDs. Two-hundred and nine dental surfaces of anterior permanent teeth were selected in patients, 6-11 years of age, with cleft lip with/without cleft palate. First, a conventional clinical examination was conducted according to the modified Developmental Defects of Enamel Index (DDE Index). Dental surfaces were evaluated using an operating microscope and a fluorescence-based device. Interexaminer reproducibility was determined using the kappa test. To compare groups, McNemar's test was used. Cramer's V test was used for comparing the distribution of index codes obtained after classification of all dental surfaces. Cramer's V test revealed statistically significant differences (P < .0001) in the distribution of index codes obtained using the different methods; the coefficients were 0.365 for conventional clinical examination versus fluorescence, 0.961 for conventional clinical examination versus operating microscope and 0.358 for operating microscope versus fluorescence. The sensitivity of the operating microscope and fluorescence method was statistically significant (P = .008 and P < .0001, respectively). Otherwise, the results did not show statistically significant differences in accuracy and specificity for either the operating microscope or the fluorescence methods. This study suggests that the operating microscope performed better than the fluorescence-based device and could be an auxiliary method for the detection of DEDs. © 2017 FDI World Dental Federation.

Active Female Maximal and Anaerobic Threshold Cardiorespiratory Responses to Six Different Water Aerobics Exercises.

PubMed

Antunes, Amanda H; Alberton, Cristine L; Finatto, Paula; Pinto, Stephanie S; Cadore, Eduardo L; Zaffari, Paula; Kruel, Luiz F M

2015-01-01

Maximal tests conducted on land are not suitable for the prescription of aquatic exercises, which makes it difficult to optimize the intensity of water aerobics classes. The aim of the present study was to evaluate the maximal and anaerobic threshold cardiorespiratory responses to 6 water aerobics exercises. Volunteers performed 3 of the exercises in the sagittal plane and 3 in the frontal plane. Twelve active female volunteers (aged 24 ± 2 years) performed 6 maximal progressive test sessions. Throughout the exercise tests, we measured heart rate (HR) and oxygen consumption (VO2). We randomized all sessions with a minimum interval of 48 hr between each session. For statistical analysis, we used repeated-measures 1-way analysis of variance. Regarding the maximal responses, for the peak VO2, abductor hop and jumping jacks (JJ) showed significantly lower values than frontal kick and cross-country skiing (CCS; p < .001; partial η(2) = .509), while for the peak HR, JJ showed statistically significantly lower responses compared with stationary running and CCS (p < .001; partial η(2) = .401). At anaerobic threshold intensity expressed as the percentage of the maximum values, no statistically significant differences were found among exercises. Cardiorespiratory responses are directly associated with the muscle mass involved in the exercise. Thus, it is worth emphasizing the importance of performing a maximal test that is specific to the analyzed exercise so the prescription of the intensity can be safer and valid.

Impact of syncope on quality of life: validation of a measure in patients undergoing tilt testing.

PubMed

Nave-Leal, Elisabete; Oliveira, Mário; Pais-Ribeiro, José; Santos, Sofia; Oliveira, Eunice; Alves, Teresa; Cruz Ferreira, Rui

2015-03-01

Recurrent syncope has a significant impact on quality of life. The development of measurement scales to assess this impact that are easy to use in clinical settings is crucial. The objective of the present study is a preliminary validation of the Impact of Syncope on Quality of Life questionnaire for the Portuguese population. The instrument underwent a process of translation, validation, analysis of cultural appropriateness and cognitive debriefing. A population of 39 patients with a history of recurrent syncope (>1 year) who underwent tilt testing, aged 52.1 ± 16.4 years (21-83), 43.5% male, most in active employment (n=18) or retired (n=13), constituted a convenience sample. The resulting Portuguese version is similar to the original, with 12 items in a single aggregate score, and underwent statistical validation, with assessment of reliability, validity and stability over time. With regard to reliability, the internal consistency of the scale is 0.9. Assessment of convergent and discriminant validity showed statistically significant results (p<0.01). Regarding stability over time, a test-retest of this instrument at six months after tilt testing with 22 patients of the sample who had not undergone any clinical intervention found no statistically significant changes in quality of life. The results indicate that this instrument is of value for assessing quality of life in patients with recurrent syncope in Portugal. Copyright © 2014 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Inappropriate Fiddling with Statistical Analyses to Obtain a Desirable P-value: Tests to Detect its Presence in Published Literature

PubMed Central

Gadbury, Gary L.; Allison, David B.

2012-01-01

Much has been written regarding p-values below certain thresholds (most notably 0.05) denoting statistical significance and the tendency of such p-values to be more readily publishable in peer-reviewed journals. Intuition suggests that there may be a tendency to manipulate statistical analyses to push a “near significant p-value” to a level that is considered significant. This article presents a method for detecting the presence of such manipulation (herein called “fiddling”) in a distribution of p-values from independent studies. Simulations are used to illustrate the properties of the method. The results suggest that the method has low type I error and that power approaches acceptable levels as the number of p-values being studied approaches 1000. PMID:23056287

Inappropriate fiddling with statistical analyses to obtain a desirable p-value: tests to detect its presence in published literature.

PubMed

Gadbury, Gary L; Allison, David B

2012-01-01

Much has been written regarding p-values below certain thresholds (most notably 0.05) denoting statistical significance and the tendency of such p-values to be more readily publishable in peer-reviewed journals. Intuition suggests that there may be a tendency to manipulate statistical analyses to push a "near significant p-value" to a level that is considered significant. This article presents a method for detecting the presence of such manipulation (herein called "fiddling") in a distribution of p-values from independent studies. Simulations are used to illustrate the properties of the method. The results suggest that the method has low type I error and that power approaches acceptable levels as the number of p-values being studied approaches 1000.

Indirect zirconia-reinforced lithium silicate ceramic CAD/CAM restorations: Preliminary clinical results after 12 months.

PubMed

Zimmermann, Moritz; Koller, Christina; Mehl, Albert; Hickel, Reinhard

2017-01-01

No clinical data are available for the new computer-aided design/computer-assisted manufacture (CAD/CAM) material zirconia-reinforced lithium silicate (ZLS) ceramic. This study describes preliminary clinical results for indirect ZLS CAD/CAM restorations after 12 months. Indirect restorations were fabricated, using the CEREC method and intraoral scanning (CEREC Omnicam, CEREC MCXL). Sixty-seven restorations were seated adhesively (baseline). Sixty restorations were evaluated after 12 months (follow-up), using modified FDI criteria. Two groups were established, according to ZLS restorations' post-processing procedure prior to adhesive seating: group I (three-step polishing, n = 32) and group II (fire glazing, n = 28). Statistical analysis was performed with Mann-Whitney U test and Wilcoxon test (P < .05). The success rate of indirect ZLS CAD/CAM restorations after 12 months was 96.7%. Two restorations clinically failed as a result of bulk fracture (failure rate 3.3%). No statistically significant differences were found for baseline and follow-up criteria (Wilcoxon test, P > .05). Statistically significant differences were found for criteria surface gloss for group I and group II (Mann-Whitney U test, P < .05). This study demonstrates ZLS CAD/CAM restorations have a high clinical success rate after 12 months. A longer clinical evaluation period is necessary to draw further conclusions.

Characterization and coating stability evaluation of nickel-titanium orthodontic esthetic wires: an in vivo study.

PubMed

Argalji, Nina; Silva, Eduardo Moreira da; Cury-Saramago, Adriana; Mattos, Claudia Trindade

2017-08-21

The objective of this study was to compare coating dimensions and surface characteristics of two different esthetic covered nickel-titanium orthodontic rectangular archwires, as-received from the manufacturer and after oral exposure. The study was designed for comparative purposes. Both archwires, as-received from the manufacturer, were observed using a stereomicroscope to measure coating thickness and inner metallic dimensions. The wires were also exposed to oral environment in 11 orthodontic active patients for 21 days. After removing the samples, stereomicroscopy images were captured, coating loss was measured and its percentage was calculated. Three segments of each wire (one as-received and two after oral exposure) were observed using scanning electron microscopy for a qualitative analysis of the labial surface of the wires. The Lilliefors test and independent t-test were applied to verify normality of data and statistical differences between wires, respectively. The significance level adopted was 0.05. The results showed that the differences between the wires while comparing inner height and thickness were statistically significant (p < 0.0001). In average, the most recently launched wire presented a coating thickness twice that of the control wire, which was also a statistically significant difference. The coating loss percentage was also statistically different (p = 0.0346) when the latest launched wire (13.27%) was compared to the control (29.63%). In conclusion, the coating of the most recent wire was thicker and more uniform, whereas the control had a thinner coating on the edges. After oral exposure, both tested wires presented coating loss, but the most recently launched wire exhibited better results.

After p Values: The New Statistics for Undergraduate Neuroscience Education.

PubMed

Calin-Jageman, Robert J

2017-01-01

Statistical inference is a methodological cornerstone for neuroscience education. For many years this has meant inculcating neuroscience majors into null hypothesis significance testing with p values. There is increasing concern, however, about the pervasive misuse of p values. It is time to start planning statistics curricula for neuroscience majors that replaces or de-emphasizes p values. One promising alternative approach is what Cumming has dubbed the "New Statistics", an approach that emphasizes effect sizes, confidence intervals, meta-analysis, and open science. I give an example of the New Statistics in action and describe some of the key benefits of adopting this approach in neuroscience education.

How allele frequency and study design affect association test statistics with misrepresentation errors.

PubMed

Escott-Price, Valentina; Ghodsi, Mansoureh; Schmidt, Karl Michael

2014-04-01

We evaluate the effect of genotyping errors on the type-I error of a general association test based on genotypes, showing that, in the presence of errors in the case and control samples, the test statistic asymptotically follows a scaled non-central $\\chi ^2$ distribution. We give explicit formulae for the scaling factor and non-centrality parameter for the symmetric allele-based genotyping error model and for additive and recessive disease models. They show how genotyping errors can lead to a significantly higher false-positive rate, growing with sample size, compared with the nominal significance levels. The strength of this effect depends very strongly on the population distribution of the genotype, with a pronounced effect in the case of rare alleles, and a great robustness against error in the case of large minor allele frequency. We also show how these results can be used to correct $p$-values.

Invited Commentary: Can Issues With Reproducibility in Science Be Blamed on Hypothesis Testing?

PubMed

Weinberg, Clarice R

2017-09-15

In the accompanying article (Am J Epidemiol. 2017;186(6):646-647), Dr. Timothy Lash makes a forceful case that the problems with reproducibility in science stem from our "culture" of null hypothesis significance testing. He notes that when attention is selectively given to statistically significant findings, the estimated effects will be systematically biased away from the null. Here I revisit the recent history of genetic epidemiology and argue for retaining statistical testing as an important part of the tool kit. Particularly when many factors are considered in an agnostic way, in what Lash calls "innovative" research, investigators need a selection strategy to identify which findings are most likely to be genuine, and hence worthy of further study. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

The Influence of Cognitive Reserve on Recovery from Traumatic Brain Injury.

PubMed

Donders, Jacobus; Stout, Jacob

2018-04-12

we sought to determine the degree to which cognitive reserve, as assessed by the Test of Premorbid Functioning in combination with demographic variables, could act as a buffer against the effect of traumatic brain injury (TBI) on cognitive test performance. retrospective analysis of a cohort of 121 persons with TBI who completed the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) within 1-12 months after injury. regression analyses indicated that cognitive reserve was a statistically significant predictor of all postinjury WAIS-IV factor index scores, after controlling for various premorbid and comorbid confounding variables. Only for Processing Speed did injury severity make an additional statistically significant contribution to the prediction model. cognitive reserve has a protective effect with regard to the impact of TBI on cognitive test performance but this effect is imperfect and does not completely negate the effect of injury severity.

Using a cross section to train veterinary students to visualize anatomical structures in three dimensions

NASA Astrophysics Data System (ADS)

Provo, Judy; Lamar, Carlton; Newby, Timothy

2002-01-01

A cross section was used to enhance three-dimensional knowledge of anatomy of the canine head. All veterinary students in two successive classes (n = 124) dissected the head; experimental groups also identified structures on a cross section of the head. A test assessing spatial knowledge of the head generated 10 dependent variables from two administrations. The test had content validity and statistically significant interrater and test-retest reliability. A live-dog examination generated one additional dependent variable. Analysis of covariance controlling for performance on course examinations and quizzes revealed no treatment effect. Including spatial skill as a third covariate revealed a statistically significant effect of spatial skill on three dependent variables. Men initially had greater spatial skill than women, but spatial skills were equal after 8 months. A qualitative analysis showed the positive impact of this experience on participants. Suggestions for improvement and future research are discussed.

Effect of Time on Gypsum-Impression Material Compatibility

NASA Astrophysics Data System (ADS)

Won, John Boram

The purpose of this study was to evaluate the compatibility of dental gypsum with three recently introduced irreversible hydrocolloid (alginate) alternatives. The test materials were Alginot® (Kerr™), Position Penta Quick® (3M ESPE™) and Silgimix ® (Sultan Dental™). The irreversible hydrocolloid impression material, Jeltrate Plus antimicrobial® (Dentsply Caulk™) served as the control. Materials and Methods: Testing of materials was conducted in accordance with ANSI/ADA Specification No. 18 for Alginate Impression Materials. Statistical Analysis: The 3-Way ANOVA test was used to analyze measurements between different time points at a significance level of (p < 0.05). Outcome: It was found that there was greater compatibility between gypsum and the alternative materials over time than the traditional irreversible hydrocolloid material that was tested. A statistically significant amount of surface change/incompatibility was found over time with the combination of the dental gypsum products and the control impression material (Jeltrate Plus antimicrobial®).

Addendum to the article: Misuse of null hypothesis significance testing: Would estimation of positive and negative predictive values improve certainty of chemical risk assessment?

PubMed

Bundschuh, Mirco; Newman, Michael C; Zubrod, Jochen P; Seitz, Frank; Rosenfeldt, Ricki R; Schulz, Ralf

2015-03-01

We argued recently that the positive predictive value (PPV) and the negative predictive value (NPV) are valuable metrics to include during null hypothesis significance testing: They inform the researcher about the probability of statistically significant and non-significant test outcomes actually being true. Although commonly misunderstood, a reported p value estimates only the probability of obtaining the results or more extreme results if the null hypothesis of no effect was true. Calculations of the more informative PPV and NPV require a priori estimate of the probability (R). The present document discusses challenges of estimating R.

Do stages of menopause affect the outcomes of pelvic floor muscle training?

PubMed

Tosun, Özge Çeliker; Mutlu, Ebru Kaya; Tosun, Gökhan; Ergenoğlu, Ahmet Mete; Yeniel, Ahmet Özgur; Malkoç, Mehtap; Aşkar, Niyazi; İtil, İsmail Mete

2015-02-01

The purpose of our study is to determine whether there is a difference in pelvic floor muscle strength attributable to pelvic floor muscle training conducted during different stages of menopause. One hundred twenty-two women with stress urinary incontinence and mixed urinary incontinence were included in this prospective controlled study. The participants included in this study were separated into three groups according to the Stages of Reproductive Aging Workshop staging system as follows: group 1 (n = 41): stages -3 and -2; group 2 (n = 32): stages +1 and -1; and group 3 (n = 30): stage +2. All three groups were provided an individual home exercise program throughout the 12-week study. Pelvic floor muscle strength before and after the 12-week treatment was measured in all participants (using the PERFECT [power, endurance, number of repetitions, and number of fast (1-s) contractions; every contraction is timed] scheme, perineometry, transabdominal ultrasound, Brink scale, pad test, and stop test). Data were analyzed using analysis of variance. There were no statistically significant differences in pre-exercise training pelvic floor muscle strength parameters among the three groups. After 12 weeks, there were statistically significant increases in PERFECT scheme, Brink scale, perineometry, and ultrasound values. In contrast, there were significant decreases in stop test and 1-hour pad test values observed in the three groups (P = 0.001, dependent t test). In comparison with the other groups, group 1 demonstrated statistically significant improvements in the following postexercise training parameters: power, repetition, speed, Brink vertical displacement, and stop test. The lowest increase was observed in group 2 (P < 0.05). Strength increase can be achieved at all stages of menopause with pelvic floor muscle training, but the rates of increase vary according to the menopausal stage of the participants. Women in the late menopausal transition and early menopause are least responsive to pelvic floor muscle strength training. Further studies in this field are needed.

A novel approach to detect test-seeking behaviour in the blood donor population: making the invisible visible.

PubMed

de Vos, A S; Lieshout-Krikke, R W; Slot, E; Cator, E A; Janssen, M P

2016-10-01

Individuals may donate blood in order to determine their infection status after exposure to an increased infection risk. Such test-seeking behaviour decreases transfusion safety. Instances of test seeking are difficult to substantiate as donors are unlikely to admit to such behaviour. However, manifestation in a population of repeat donors may be determined using statistical inference. Test-seeking donors would be highly motivated to donate following infection risk, influencing the timing of their donation. Donation intervals within 2005-2014 of all Dutch blood donors who acquired syphilis (N = 50), HIV (N = 13), HTLV (N = 4) or HCV (N = 2) were compared to donation intervals of uninfected blood donors (N = 7 327 836) using the Anderson-Darling test. We adjusted for length bias as well as for age, gender and donation type of the infected. Additionally, the power of the proposed method was investigated by simulation. Among the Dutch donors who acquired infection, we found only a non-significant overrepresentation of short donation intervals (P = 0·54). However, we show by simulation that both relatively short and long donation intervals among infected donors can reveal test seeking. The power of the method is >90% if among 69 infected donors >35 (51%) are test seeking, or if among 320 infected donors >90 (30%) are test seeking. We show how statistical analysis may be used to reveal the extent of test seeking in repeat blood donor populations. In the Dutch setting, indications for test-seeking behaviour were not statistically significant. This may, however, be due to the low number of infected individuals. © 2016 International Society of Blood Transfusion.

Influence of manufacturing parameters on the strength of PLA parts using Layered Manufacturing technique: A statistical approach

NASA Astrophysics Data System (ADS)

Jaya Christiyan, K. G.; Chandrasekhar, U.; Mathivanan, N. Rajesh; Venkateswarlu, K.

2018-02-01

A 3D printing was successfully used to fabricate samples of Polylactic Acid (PLA). Processing parameters such as Lay-up speed, Lay-up thickness, and printing nozzle were varied. All samples were tested for flexural strength using three point load test. A statistical mathematical model was developed to correlate the processing parameters with flexural strength. The result clearly demonstrated that the lay-up thickness and nozzle diameter influenced flexural strength significantly, whereas lay-up speed hardly influenced the flexural strength.

Quality of life and self-esteem of persons with paraplegia living in São Paulo, Brazil.

PubMed

Blanes, Leila; Carmagnani, Maria Isabel S; Ferreira, Lydia M

2009-02-01

To evaluate the quality of life (QoL) and self-esteem of paraplegic persons. The sample consisted of 60 outpatients with traumatic paraplegia living in São Paulo, Brazil, from whom clinical and demographic data were obtained. QoL was assessed by the 36-item Short-Form (SF-36) health survey questionnaire, and self-esteem was measured by Rosenberg's Self-Esteem (RSE) scale. Statistical analysis was performed using Student's t-test, analysis of variance and Fisher's least significant difference (LSD) test at a significance level of 5%. Participants were predominately men (86.7%) with a mean age of 32.9 (standard deviation [SD] = 9.47) years, low education level and low income. The SF-36 dimensions that received the lowest scores were physical functioning, role physical and role emotional. Cronbach's alpha for the SF-36 questionnaire was 0.80. A significant statistical difference was found between the presence of pressure ulcers and low scores on mental health (P = 0.001), as determined by Student's t-test. The mean self-esteem score was 8.35 and there was a significant statistical difference between low self-esteem scores and occupation (P = 0.008). Participants reported low QoL and self-esteem. The results provide background information that may be useful in the development of strategies to reduce the impact of spinal cord injury (SCI) on the life and health of persons with SCI, improving their QoL.

Bending properties of a new nickel-titanium alloy with a lower percent by weight of nickel.

PubMed

Testarelli, Luca; Plotino, Gianluca; Al-Sudani, Dina; Vincenzi, Valentina; Giansiracusa, Alessio; Grande, Nicola M; Gambarini, Gianluca

2011-09-01

The aim of the present study was to evaluate the bending properties of Hyflex instruments, which exhibit a lower percent in weight of nickel (52 Ni %wt) and compare them with other commercially available nickel-titanium (NiTi) rotary instruments. Ten instruments with tip size 25, 0.06 taper of each of the following NiTi rotary instrumentation techniques were selected for the study: Hyflex, EndoSequence, ProFile, Hero, and Flexmasters. All instruments from each group were tested for stiffness by comparing their bending moment when they attained a 45-degree bend. Experimental procedures strictly followed testing methodology described in ISO 3630-1. All data were recorded and subjected to statistical evaluation by using analysis of variance test. Statistical significance was set at P < .05). Statistical analysis of the data revealed that Hyflex files were found to be the most flexible instruments, with a significant difference (P < .05) in comparison with the other instruments. Among the other files, a significant difference has been reported for EndoSequence instruments compared with ProFile, Hero, and FlexMaster (P < .05), whereas no significant differences have been reported among those 3 files (P > .05). Results of the present study have illustrated an increased flexibility of the new NiTi alloy over conventional NiTi alloy, and they highlight the potential of the new manufacturing process. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Relationship of Attention Deficit Hyperactivity Disorder and Postconcussion Recovery in Youth Athletes.

PubMed

Mautner, Kenneth; Sussman, Walter I; Axtman, Matthew; Al-Farsi, Yahya; Al-Adawi, Samir

2015-07-01

To investigate whether attention deficit hyperactivity disorder (ADHD) influences postconcussion recovery, as measured by computerized neurocognitive testing. This is a retrospective case control study. Computer laboratories across 10 high schools in the greater Atlanta, Georgia area. Immediate postconcussion assessment and cognitive testing (ImPACT) scores of 70 athletes with a self-reported diagnosis of ADHD and who sustained a sport-related concussion were compared with a randomly selected age-matched control group. Immediate postconcussion assessment and cognitive testing scores over a 5-year interval were reviewed for inclusion. Postconcussion recovery was defined as a return to equivalent baseline neurocognitive score on the ImPACT battery, and a concussion symptom score of ≤7. Athletes with ADHD had on average a longer time to recovery when compared with the control group (16.5 days compared with 13.5 days), although not statistically significant. The number of previous concussions did not have any effect on the rate of recovery in the ADHD or the control group. In addition, baseline neurocognitive testing did not statistically differ between the 2 groups, except in verbal memory. Although not statistically significant, youth athletes with ADHD took on average 3 days longer to return to baseline neurocognitive testing compared with a control group without ADHD. Youth athletes with ADHD may have a marginally prolonged recovery as indexed by neurocognitive testing and should be considered when prognosticating time to recovery in this subset of student athletes.

PROMISE: a tool to identify genomic features with a specific biologically interesting pattern of associations with multiple endpoint variables

PubMed Central

Pounds, Stan; Cheng, Cheng; Cao, Xueyuan; Crews, Kristine R.; Plunkett, William; Gandhi, Varsha; Rubnitz, Jeffrey; Ribeiro, Raul C.; Downing, James R.; Lamba, Jatinder

2009-01-01

Motivation: In some applications, prior biological knowledge can be used to define a specific pattern of association of multiple endpoint variables with a genomic variable that is biologically most interesting. However, to our knowledge, there is no statistical procedure designed to detect specific patterns of association with multiple endpoint variables. Results: Projection onto the most interesting statistical evidence (PROMISE) is proposed as a general procedure to identify genomic variables that exhibit a specific biologically interesting pattern of association with multiple endpoint variables. Biological knowledge of the endpoint variables is used to define a vector that represents the biologically most interesting values for statistics that characterize the associations of the endpoint variables with a genomic variable. A test statistic is defined as the dot-product of the vector of the observed association statistics and the vector of the most interesting values of the association statistics. By definition, this test statistic is proportional to the length of the projection of the observed vector of correlations onto the vector of most interesting associations. Statistical significance is determined via permutation. In simulation studies and an example application, PROMISE shows greater statistical power to identify genes with the interesting pattern of associations than classical multivariate procedures, individual endpoint analyses or listing genes that have the pattern of interest and are significant in more than one individual endpoint analysis. Availability: Documented R routines are freely available from www.stjuderesearch.org/depts/biostats and will soon be available as a Bioconductor package from www.bioconductor.org. Contact: stanley.pounds@stjude.org Supplementary information: Supplementary data are available at Bioinformatics online. PMID:19528086

Pathway analysis with next-generation sequencing data.

PubMed

Zhao, Jinying; Zhu, Yun; Boerwinkle, Eric; Xiong, Momiao

2015-04-01

Although pathway analysis methods have been developed and successfully applied to association studies of common variants, the statistical methods for pathway-based association analysis of rare variants have not been well developed. Many investigators observed highly inflated false-positive rates and low power in pathway-based tests of association of rare variants. The inflated false-positive rates and low true-positive rates of the current methods are mainly due to their lack of ability to account for gametic phase disequilibrium. To overcome these serious limitations, we develop a novel statistic that is based on the smoothed functional principal component analysis (SFPCA) for pathway association tests with next-generation sequencing data. The developed statistic has the ability to capture position-level variant information and account for gametic phase disequilibrium. By intensive simulations, we demonstrate that the SFPCA-based statistic for testing pathway association with either rare or common or both rare and common variants has the correct type 1 error rates. Also the power of the SFPCA-based statistic and 22 additional existing statistics are evaluated. We found that the SFPCA-based statistic has a much higher power than other existing statistics in all the scenarios considered. To further evaluate its performance, the SFPCA-based statistic is applied to pathway analysis of exome sequencing data in the early-onset myocardial infarction (EOMI) project. We identify three pathways significantly associated with EOMI after the Bonferroni correction. In addition, our preliminary results show that the SFPCA-based statistic has much smaller P-values to identify pathway association than other existing methods.

Effect of structural parameters on burning behavior of polyester fabrics having flame retardancy property

NASA Astrophysics Data System (ADS)

Çeven, E. K.; Günaydın, G. K.

2017-10-01

The aim of this study is filling the gap in the literature about investigating the effect of yarn and fabric structural parameters on burning behavior of polyester fabrics. According to the experimental design three different fabric types, three different weft densities and two different weave types were selected and a total of eighteen different polyester drapery fabrics were produced. All statistical procedures were conducted using the SPSS Statistical software package. The results of the Analysis of Variance (ANOVA) tests indicated that; there were statistically significant (5% significance level) differences between the mass loss ratios (%) in weft and mass loss ratios (%) in warp direction of different fabrics calculated after the flammability test. The Student-Newman-Keuls (SNK) results for mass loss ratios (%) both in weft and warp directions revealed that the mass loss ratios (%) of fabrics containing Trevira CS type polyester were lower than the mass loss ratios of polyester fabrics subjected to washing treatment and flame retardancy treatment.

Non-arbitrage in financial markets: A Bayesian approach for verification

NASA Astrophysics Data System (ADS)

Cerezetti, F. V.; Stern, Julio Michael

2012-10-01

The concept of non-arbitrage plays an essential role in finance theory. Under certain regularity conditions, the Fundamental Theorem of Asset Pricing states that, in non-arbitrage markets, prices of financial instruments are martingale processes. In this theoretical framework, the analysis of the statistical distributions of financial assets can assist in understanding how participants behave in the markets, and may or may not engender arbitrage conditions. Assuming an underlying Variance Gamma statistical model, this study aims to test, using the FBST - Full Bayesian Significance Test, if there is a relevant price difference between essentially the same financial asset traded at two distinct locations. Specifically, we investigate and compare the behavior of call options on the BOVESPA Index traded at (a) the Equities Segment and (b) the Derivatives Segment of BM&FBovespa. Our results seem to point out significant statistical differences. To what extent this evidence is actually the expression of perennial arbitrage opportunities is still an open question.

Usual Dose of Caffeine Has a Positive Effect on Somatosensory Related Postural Stability in Hemiparetic Stroke Patients

PubMed Central

Kim, Woo Sub; Choi, Chang Kweon; Yoon, Sang Ho

2014-01-01

Objective To evaluate the effect of caffeine on balance control of hemiparetic stroke patients, we investigated the difference in postural stability before and after drinking coffee by observing changes in stability index (SI) from posturography. Methods Thirty patients with history of stroke and 15 age-matched healthy subjects participated in this study. Effect of group factor (of the control and stroke groups) and treatment factor (pre- and post-drinking of coffee) on SI were tested in three conditions: with eyes opened, with eyes closed, and with a pillow support. The effects of these factors on visual deprivation and somatosensory change of subjects were also tested. Results Under all conditions, SI was higher in the stroke group than in the control group. Under eyes-open condition, the treatment factor was not statistically significant. Under eyes-closed condition, the interaction between group and treatment factor was statistically significant. After the subjects drank coffee, SI in the control group was increased. However, SI in the stroke group was decreased. Under pillow-supported condition, the interaction between group and treatment factor appeared marginally significant. For visual deprivation effect, the interaction between treatment and group factor was statistically significant. After caffeine consumption, the visual deprivation effect was increased in control group but decreased in the stroke group. For somatosensory change effect, the interaction between group and treatment factor was not statistically significant. Conclusion Postural stability of hemiparetic stroke patients related to somatosensory information was improved after intake of usual dose of caffeine. PMID:25566476

Similarity in Bilateral Isolated Internal Orbital Fractures.

PubMed

Chen, Hung-Chang; Cox, Jacob T; Sanyal, Abanti; Mahoney, Nicholas R

2018-04-13

In evaluating patients sustaining bilateral isolated internal orbital fractures, the authors have observed both similar fracture locations and also similar expansion of orbital volumes. In this study, we aim to investigate if there is a propensity for the 2 orbits to fracture in symmetrically similar patterns when sustaining similar trauma. A retrospective chart review was performed studying all cases at our institution of bilateral isolated internal orbital fractures involving the medial wall and/or the floor at the time of presentation. The similarity of the bilateral fracture locations was evaluated using the Fisher's exact test. The bilateral expanded orbital volumes were analyzed using the Wilcoxon signed-rank test to assess for orbital volume similarity. Twenty-four patients with bilateral internal orbital fractures were analyzed for fracture location similarity. Seventeen patients (70.8%) had 100% concordance in the orbital subregion fractured, and the association between the right and the left orbital fracture subregion locations was statistically significant (P < 0.0001). Fifteen patients were analyzed for orbital volume similarity. The average orbital cavity volume was 31.2 ± 3.8 cm on the right and 32.0 ± 3.7 cm on the left. There was a statistically significant difference between right and left orbital cavity volumes (P = 0.0026). The data from this study suggest that an individual who suffers isolated bilateral internal orbital fractures has a statistically significant similarity in the location of their orbital fractures. However, there does not appear to be statistically significant similarity in the expansion of the orbital volumes in these patients.

Effect of Nocturnal Intermittent Peritoneal Dialysis on Intraocular Pressure and Anterior Segment Optical Coherence Tomography Parameters.

PubMed

Chong, Ka Lung; Samsudin, Amir; Keng, Tee Chau; Kamalden, Tengku Ain; Ramli, Norlina

2017-02-01

To evaluate the effect of nocturnal intermittent peritoneal dialysis (NIPD) on intraocular pressure (IOP) and anterior segment optical coherence tomography (ASOCT) parameters. Systemic changes associated with NIPD were also analyzed. Observational study. Nonglaucomatous patients on NIPD underwent systemic and ocular assessment including mean arterial pressure (MAP), body weight, serum osmolarity, visual acuity, IOP measurement, and ASOCT within 2 hours both before and after NIPD. The Zhongshan Angle Assessment Program (ZAAP) was used to measure ASOCT parameters including anterior chamber depth, anterior chamber width, anterior chamber area, anterior chamber volume, lens vault, angle opening distance, trabecular-iris space area, and angle recess area. T tests and Pearson correlation tests were performed with P<0.05 considered statistically significant. A total of 46 eyes from 46 patients were included in the analysis. There were statistically significant reductions in IOP (-1.8±0.6 mm Hg, P=0.003), MAP (-11.9±3.1 mm Hg, P<0.001), body weight (-0.7±2.8 kg, P<0.001), and serum osmolarity (-3.4±2.0 mOsm/L, P=0.002) after NIPD. All the ASOCT parameters did not have any statistically significant changes after NIPD. There were no statistically significant correlations between the changes in IOP, MAP, body weight, and serum osmolarity (all P>0.05). NIPD results in reductions in IOP, MAP, body weight, and serum osmolarity in nonglaucomatous patients.

Zebrafish embryo toxicity of anaerobic biotransformation products from the insensitive munitions compound 2,4-dinitroanisole.

PubMed

Olivares, Christopher I; Sierra-Alvarez, Reyes; Abrell, Leif; Chorover, Jon; Simonich, Michael; Tanguay, Robert L; Field, Jim A

2016-11-01

2,4-Dinitroanisole (DNAN) is an emerging insensitive munitions compound that readily undergoes anaerobic nitro-group reduction to 2-methoxy-5-nitroaniline (MENA) and 2,4-diaminoanisole (DAAN), followed by formation of unique azo dimers. Currently there is little knowledge on the ecotoxicity of DNAN (bio)transformation products. In the present study, mortality, development, and behavioral effects of DNAN (bio)transformation products were assessed using zebrafish (Danio rerio) embryos. The authors tested individual products, MENA and DAAN, as well as dimer and trimer surrogates. As pure compounds, 3-nitro-4-methoxyaniline and 2,2'-dimethoxy-4,4'-azodianiline caused statistically significant effects, with lowest-observable-adverse effect levels (LOAEL) at 6.4 μM on 1 or 2 developmental endpoints, respectively. The latter had 6 additional statistically significant developmental endpoints with LOAELs of 64 μM. Based on light-to-dark swimming behavioral tests, DAAN (640 μM) caused reduction in swimming, suggestive of neurotoxicity. No statistically significant mortality occurred (≤64 μM) for any of the individual compounds. However, metabolite mixtures formed during different stages of MENA (bio)transformation in soil were characterized using high-resolution mass spectrometry in parallel with zebrafish embryo toxicity assays, which demonstrated statistically significant mortality during the onset of azo-dimer formation. Overall the results indicate that several DNAN (bio)transformation products cause different types of toxicity to zebrafish embryos. Environ Toxicol Chem 2016;35:2774-2781. © 2016 SETAC. © 2016 SETAC.

Single-row, double-row, and transosseous equivalent techniques for isolated supraspinatus tendon tears with minimal atrophy: A retrospective comparative outcome and radiographic analysis at minimum 2-year followup

PubMed Central

McCormick, Frank; Gupta, Anil; Bruce, Ben; Harris, Josh; Abrams, Geoff; Wilson, Hillary; Hussey, Kristen; Cole, Brian J.

2014-01-01

Purpose: The purpose of this study was to measure and compare the subjective, objective, and radiographic healing outcomes of single-row (SR), double-row (DR), and transosseous equivalent (TOE) suture techniques for arthroscopic rotator cuff repair. Materials and Methods: A retrospective comparative analysis of arthroscopic rotator cuff repairs by one surgeon from 2004 to 2010 at minimum 2-year followup was performed. Cohorts were matched for age, sex, and tear size. Subjective outcome variables included ASES, Constant, SST, UCLA, and SF-12 scores. Objective outcome variables included strength, active range of motion (ROM). Radiographic healing was assessed by magnetic resonance imaging (MRI). Statistical analysis was performed using analysis of variance (ANOVA), Mann — Whitney and Kruskal — Wallis tests with significance, and the Fisher exact probability test <0.05. Results: Sixty-three patients completed the study requirements (20 SR, 21 DR, 22 TOE). There was a clinically and statistically significant improvement in outcomes with all repair techniques (ASES mean improvement P = <0.0001). The mean final ASES scores were: SR 83; (SD 21.4); DR 87 (SD 18.2); TOE 87 (SD 13.2); (P = 0.73). There was a statistically significant improvement in strength for each repair technique (P < 0.001). There was no significant difference between techniques across all secondary outcome assessments: ASES improvement, Constant, SST, UCLA, SF-12, ROM, Strength, and MRI re-tear rates. There was a decrease in re-tear rates from single row (22%) to double-row (18%) to transosseous equivalent (11%); however, this difference was not statistically significant (P = 0.6). Conclusions: Compared to preoperatively, arthroscopic rotator cuff repair, using SR, DR, or TOE techniques, yielded a clinically and statistically significant improvement in subjective and objective outcomes at a minimum 2-year follow-up. Level of Evidence: Therapeutic level 3. PMID:24926159

Laboratory examination of seronegative and seropositive rheumatoid arthritis.

PubMed

Sahatçiu-Meka, Vjollca; Anton, Kukeli

2010-01-01

In response to the continuing debate whether seronegative and seropositive rheumatoid arthritis (RA) are parts of the same disease spectrum or are distinct disorders, we performed a comparative analysis of some laboratory characteristics. The test group consisted of 125 seronegative RA(93 female, 32 male), with titers lower than 1/64 as defined by Rose-Waaler test. The control group consisted of 125 seropositive RA patients (93 female, 32 male), with titers of 1/64 or higher. Patients all belonged to the 2nd and 3rd functional classes (ARA), and were between 25-60 years of age. The duration of the disease was 1-27 years. Elevated average values of erythrosedimentation (ERS), C-reactive protein (PCR) and erythrocytes (Er) were found in seropositive patients, but they did not present statistically significant difference with regard to sero-status. Reduced values of hemoglobin (Hb) were found more frequently in seropositive patients (t = 2.26, p < 0.05), especially female seropositive patients (t = 4.38, p < 0.01), without correlation to disability and duration of the disease. Statistically significant difference was found in average values of fibrinogen in the seropositive subset (t = 2.10, p < 0.05), especially in female seropositive patients (t = 2.65, p < 0.01), and in average values of leukocytes (t = 1.37, p < 0.05) among male seropositive patients. Elevated immunoglobulin (IgM) values were more prominent in the seropositive subset (chi2 = 47.6, p < 0.01), especially among seropositive females (chi2 = 35.68, p < 0.01). Values of IgA and IgG did not present statistically significant difference with regard to sero-status. Levels of C3 and C4 components of the complement were reduced in seropositive tested subjects, without significant difference between sero-subsets. Increased values of gamma-globulin were confirmed with statistical significance (chi2 = 3.39, p < 0.05) in seropositive subjects, while alpha-2 globulin values were nearly equally distributed in both subsets.

Influence of the processing route of porcelain/Ti-6Al-4V interfaces on shear bond strength.

PubMed

Toptan, Fatih; Alves, Alexandra C; Henriques, Bruno; Souza, Júlio C M; Coelho, Rui; Silva, Filipe S; Rocha, Luís A; Ariza, Edith

2013-04-01

This study aims at evaluating the two-fold effect of initial surface conditions and dental porcelain-to-Ti-6Al-4V alloy joining processing route on the shear bond strength. Porcelain-to-Ti-6Al-4V samples were processed by conventional furnace firing (porcelain-fused-to-metal) and hot pressing. Prior to the processing, Ti-6Al-4V cylinders were prepared by three different surface treatments: polishing, alumina or silica blasting. Within the firing process, polished and alumina blasted samples were subjected to two different cooling rates: air cooling and a slower cooling rate (65°C/min). Metal/porcelain bond strength was evaluated by shear bond test. The data were analyzed using one-way ANOVA followed by Tuckey's test (p<0.05). Before and after shear bond tests, metallic surfaces and metal/ceramic interfaces were examined by Field Emission Gun Scanning Electron Microscope (FEG-SEM) equipped with Energy Dispersive X-Ray Spectroscopy (EDS). Shear bond strength values of the porcelain-to-Ti-6Al-4V alloy interfaces ranged from 27.1±8.9MPa for porcelain fused to polished samples up to 134.0±43.4MPa for porcelain fused to alumina blasted samples. According to the statistical analysis, no significant difference were found on the shear bond strength values for different cooling rates. Processing method was statistically significant only for the polished samples, and airborne particle abrasion was statistically significant only for the fired samples. The type of the blasting material did not cause a statistically significant difference on the shear bond strength values. Shear bond strength of dental porcelain to Ti-6Al-4V alloys can be significantly improved from controlled conditions of surface treatments and processing methods. Copyright © 2013 Elsevier Ltd. All rights reserved.

Statistical analysis of effective singular values in matrix rank determination

NASA Technical Reports Server (NTRS)

Konstantinides, Konstantinos; Yao, Kung

1988-01-01

A major problem in using SVD (singular-value decomposition) as a tool in determining the effective rank of a perturbed matrix is that of distinguishing between significantly small and significantly large singular values to the end, conference regions are derived for the perturbed singular values of matrices with noisy observation data. The analysis is based on the theories of perturbations of singular values and statistical significance test. Threshold bounds for perturbation due to finite-precision and i.i.d. random models are evaluated. In random models, the threshold bounds depend on the dimension of the matrix, the noisy variance, and predefined statistical level of significance. Results applied to the problem of determining the effective order of a linear autoregressive system from the approximate rank of a sample autocorrelation matrix are considered. Various numerical examples illustrating the usefulness of these bounds and comparisons to other previously known approaches are given.

The use and misuse of statistical analyses. [in geophysics and space physics

NASA Technical Reports Server (NTRS)

Reiff, P. H.

1983-01-01

The statistical techniques most often used in space physics include Fourier analysis, linear correlation, auto- and cross-correlation, power spectral density, and superposed epoch analysis. Tests are presented which can evaluate the significance of the results obtained through each of these. Data presented without some form of error analysis are frequently useless, since they offer no way of assessing whether a bump on a spectrum or on a superposed epoch analysis is real or merely a statistical fluctuation. Among many of the published linear correlations, for instance, the uncertainty in the intercept and slope is not given, so that the significance of the fitted parameters cannot be assessed.

Effects of Math Anxiety and Perfectionism on Timed versus Untimed Math Testing in Mathematically Gifted Sixth Graders

ERIC Educational Resources Information Center

Tsui, Joanne M.; Mazzocco, Michele M. M.

2006-01-01

This study was designed to examine the effects of math anxiety and perfectionism on math performance, under timed testing conditions, among mathematically gifted sixth graders. We found that participants had worse math performance during timed versus untimed testing, but this difference was statistically significant only when the timed condition…

Multiple-Choice versus Constructed-Response Tests in the Assessment of Mathematics Computation Skills.

ERIC Educational Resources Information Center

Gadalla, Tahany M.

The equivalence of multiple-choice (MC) and constructed response (discrete) (CR-D) response formats as applied to mathematics computation at grade levels two to six was tested. The difference between total scores from the two response formats was tested for statistical significance, and the factor structure of items in both response formats was…

Directional and Non-directional Hypothesis Testing: A Survey of SIG Members, Journals, and Textbooks.

ERIC Educational Resources Information Center

McNeil, Keith

The use of directional and nondirectional hypothesis testing was examined from the perspectives of textbooks, journal articles, and members of editorial boards. Three widely used statistical texts were reviewed in terms of how directional and nondirectional tests of significance were presented. Texts reviewed were written by: (1) D. E. Hinkle, W.…

A comparative evaluation of dental caries status among hearing-impaired and normal children of Malda, West Bengal, evaluated with the Caries Assessment Spectrum and Treatment.

PubMed

Kar, Sudipta; Kundu, Goutam; Maiti, Shyamal Kumar; Ghosh, Chiranjit; Bazmi, Badruddin Ahamed; Mukhopadhyay, Santanu

2016-01-01

Dental caries is one of the major modern-day diseases of dental hard tissue. It may affect both normal and hearing-impaired children. This study is aimed to evaluate and compare the prevalence of dental caries in hearing-impaired and normal children of Malda, West Bengal, utilizing the Caries Assessment Spectrum and Treatment (CAST). In a cross-sectional, case-control study of dental caries status of 6-12-year-old children was assessed. Statistically significant difference was found in studied (hearing-impaired) and control group (normal children). In the present study, caries affected hearing-impaired children found to be about 30.51% compared to 15.81% in normal children, and the result was statistically significant. Regarding individual caries assessment criteria, nearly all subgroups reflect statistically significant difference except sealed tooth structure group, internal caries-related discoloration in dentin, and distinct cavitation into dentine group, and the result is significant at P < 0.05. Statistical analysis was carried out utilizing Z-test. Statistically significant difference was found in studied (hearing-impaired) and control group (normal children). In the present study, caries effected hearing-impaired children found about 30.51% instead of 15.81% in normal children, and the result was statistically significant (P < 0.05). Regarding individual caries assessment criteria, nearly all subgroups reflect statistically significant difference except sealed tooth structure group, internal caries-related discoloration in dentin, and distinct cavitation into dentine group. Dental health of hearing-impaired children was found unsatisfactory than normal children when studied in relation to dental caries status evaluated with CAST.

Investigations of interference between electromagnetic transponders and wireless MOSFET dosimeters: a phantom study.

PubMed

Su, Zhong; Zhang, Lisha; Ramakrishnan, V; Hagan, Michael; Anscher, Mitchell

2011-05-01

To evaluate both the Calypso Systems' (Calypso Medical Technologies, Inc., Seattle, WA) localization accuracy in the presence of wireless metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters of dose verification system (DVS, Sicel Technologies, Inc., Morrisville, NC) and the dosimeters' reading accuracy in the presence of wireless electromagnetic transponders inside a phantom. A custom-made, solid-water phantom was fabricated with space for transponders and dosimeters. Two inserts were machined with positioning grooves precisely matching the dimensions of the transponders and dosimeters and were arranged in orthogonal and parallel orientations, respectively. To test the transponder localization accuracy with/without presence of dosimeters (hypothesis 1), multivariate analyses were performed on transponder-derived localization data with and without dosimeters at each preset distance to detect statistically significant localization differences between the control and test sets. To test dosimeter dose-reading accuracy with/without presence of transponders (hypothesis 2), an approach of alternating the transponder presence in seven identical fraction dose (100 cGy) deliveries and measurements was implemented. Two-way analysis of variance was performed to examine statistically significant dose-reading differences between the two groups and the different fractions. A relative-dose analysis method was also used to evaluate transponder impact on dose-reading accuracy after dose-fading effect was removed by a second-order polynomial fit. Multivariate analysis indicated that hypothesis 1 was false; there was a statistically significant difference between the localization data from the control and test sets. However, the upper and lower bounds of the 95% confidence intervals of the localized positional differences between the control and test sets were less than 0.1 mm, which was significantly smaller than the minimum clinical localization resolution of 0.5 mm. For hypothesis 2, analysis of variance indicated that there was no statistically significant difference between the dosimeter readings with and without the presence of transponders. Both orthogonal and parallel configurations had difference of polynomial-fit dose to measured dose values within 1.75%. The phantom study indicated that the Calypso System's localization accuracy was not affected clinically due to the presence of DVS wireless MOSFET dosimeters and the dosimeter-measured doses were not affected by the presence of transponders. Thus, the same patients could be implanted with both transponders and dosimeters to benefit from improved accuracy of radiotherapy treatments offered by conjunctional use of the two systems.

TRAN-STAT: statistics for environmental transuranic studies, July 1978, Number 5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This issue is concerned with nonparametric procedures for (1) estimating the central tendency of a population, (2) describing data sets through estimating percentiles, (3) estimating confidence limits for the median and other percentiles, (4) estimating tolerance limits and associated numbers of samples, and (5) tests of significance and associated procedures for a variety of testing situations (counterparts to t-tests and analysis of variance). Some characteristics of several nonparametric tests are illustrated using the NAEG /sup 241/Am aliquot data presented and discussed in the April issue of TRAN-STAT. Some of the statistical terms used here are defined in a glossary. Themore » reference list also includes short descriptions of nonparametric books. 31 references, 3 figures, 1 table.« less

Speech-evoked Brainstem Auditory Responses and Auditory Processing Skills: A Correlation in Adults with Hearing Loss

PubMed Central

Sanguebuche, Taissane Rodrigues; Peixe, Bruna Pias; Bruno, Rúbia Soares; Biaggio, Eliara Pinto Vieira; Garcia, Michele Vargas

2018-01-01

Introduction  The auditory system consists of sensory structures and central connections. The evaluation of the auditory pathway at a central level can be performed through behavioral and electrophysiological tests, because they are complementary to each other and provide important information about comprehension. Objective  To correlate the findings of speech brainstem-evoked response audiometry with the behavioral tests Random Gap Detection Test and Masking Level Difference in adults with hearing loss. Methods  All patients were submitted to a basic audiological evaluation, to the aforementioned behavioral tests, and to an electrophysiological assessment, by means of click-evoked and speech-evoked brainstem response audiometry. Results  There were no statistically significant values among the electrophysiological test and the behavioral tests. However, there was a significant correlation between the V and A waves, as well as the D and F waves, of the speech-evoked brainstem response audiometry peaks. Such correlations are positive, indicating that the increase of a variable implies an increase in another and vice versa. Conclusion  It was possible to correlate the findings of the speech-evoked brainstem response audiometry with those of the behavioral tests Random Gap Detection and Masking Level Difference. However, there was no statistically significant correlation between them. This shows that the electrophysiological evaluation does not depend uniquely on the behavioral skills of temporal resolution and selective attention. PMID:29379574

Anger and depression levels of mothers with premature infants in the neonatal intensive care unit.

PubMed

Kardaşözdemir, Funda; AKGüN Şahin, Zümrüt

2016-02-04

The aim of this study was to examine anger and depression levels of mothers who had a premature infant in the NICU, and all factors affecting the situation. This descriptive study was performed in the level I and II units of NICU at three state hospitals in Turkey. The data was collected with a demographic questionnaire, "Beck Depression Inventory" and "Anger Expression Scale". Descriptive statistics, parametric and nonparametric statistical tests and Pearson correlation were used in the data analysis. Mothers whose infants are under care in NICU have moderate depression. It has also been determined that mothers' educational level, income level and gender of infants were statistically significant (p <0.05). A positive relationship between depression and trait anger scores was found to be statistically significant. A negative relationship existed between depression and anger-control scores for the mothers, which was statistically significant (p <0.05). Due to the results of research, recommended that mothers who are at risk of depression and anger in the NICU evaluated by nurses and these nurses to develop their consulting roles.

Investigation of the Role of Training Health Volunteers in Promoting Pap Smear Test Use among Iranian Women Based on the Protection Motivation Theory.

PubMed

Ghahremani, Leila; Harami, Zahra Khiyali; Kaveh, Mohammad Hossein; Keshavarzi, Sareh

2016-01-01

Cervical cancer is known as one of the most prevalent types of cancers and a major public health problem in developing countries which can be detected by Pap test, prevented, and treated. Despite the effective role of Pap test in decreasing the incidence and mortality due to cervical cancer, it is still one the most common causes of cancer-related deaths among women, especially in developing countries. Thus, this study aimed to examine the effect of educational interventions implemented by health volunteers based on protection motivation theory (PMT) on promoting Pap test use among women. This quasi-experimental study was conducted on 60 health volunteers and 420 women. The study participants were divided into an intervention and a control group. Data were collected using a valid self-reported questionnaire including demographic variables and PMT constructs which was completed by both groups before and 2 months after the intervention. Then, the data were entered into the SPSS statistical software, version 19 and were analyzed using Chi-square test, independent T-test, and descriptive statistical methods. P<0.05 was considered as statistically significant. The findings of this study showed that the mean scores of PMT constructs (i.e. perceived vulnerability, perceived severity, fear, response-costs, self-efficacy, and intention) increased in the intervention group after the intervention (P<0.001). However, no significant difference was found between the two groups regarding response efficacy after the intervention (P=0.06). The rate of Pap test use also increased by about 62.9% among the study women. This study showed a significant positive relationship between PMT-based training and Pap test use. The results also revealed the successful contribution of health volunteers to training cervical cancer screening. Thus, training interventions based on PMT are suggested to be designed and implemented and health volunteers are recommended to be employed for educational purposes and promoting the community's, especially women's, health.

Statistical methods for the beta-binomial model in teratology.

PubMed Central

Yamamoto, E; Yanagimoto, T

1994-01-01

The beta-binomial model is widely used for analyzing teratological data involving littermates. Recent developments in statistical analyses of teratological data are briefly reviewed with emphasis on the model. For statistical inference of the parameters in the beta-binomial distribution, separation of the likelihood introduces an likelihood inference. This leads to reducing biases of estimators and also to improving accuracy of empirical significance levels of tests. Separate inference of the parameters can be conducted in a unified way. PMID:8187716

Efficacy of double mirrored omega pattern for skin sparing mastectomy to reduce ischemic complications.

PubMed

Santanelli di Pompeo, Fabio; Sorotos, Michail; Laporta, Rosaria; Pagnoni, Marco; Longo, Benedetto

2018-02-01

Excellent cosmetic results from skin-sparing mastectomy (SSM) are often impaired by skin flaps' necrosis (SFN), from 8%-25% or worse in smokers. This study prospectively investigated the efficacy of Double-Mirrored Omega Pattern (DMOP-SSM) compared to Wise Pattern SSM (WP-SSM) for immediate reconstruction in moderate/large-breasted smokers. From 2008-2010, DMOP-SSM was performed in 51 consecutive immediate breast reconstructions on 41 smokers (mean age = 49.8 years) with moderate/large and ptotic breasts. This active group (AG) was compared to a similar historical control group (CG) of 37 smokers (mean age = 51.1 years) who underwent WP-SSM and immediate breast reconstruction, with a mean follow-up of 37.6 months. Skin ischaemic complications, number of surgical revisions, time to wound healing, and patient satisfaction were analysed. Descriptive statistics were reported and comparison of performance endpoints was performed using Fisher's exact test and Mann-Whitney U-test. A p-value <.05 was considered significant. Patients' mean age (p = .316) and BMI (p = .215) were not statistically different between groups. Ischaemic complications occurred in 11.7% of DMOP-SSMs and in 32.4% of WP-SSMs (p = .017), and revision rates were, respectively, 5.8% and 24.3% (p = .012), both statistically significant. Mean time to wound healing was, respectively, 16.8 days and 18.4 days (p = .205). Mean patients' satisfaction scores were, respectively, 18.9 and 21.1, statistically significant (p = .022). Although tobacco use in moderate/large breasted patients can severely impair outcomes of breast reconstruction, the DMOP-SSM approach, compared to WP-SSM, allows smokers to benefit from SSM, but with statistically significant reduced skin flaps ischaemic complications, revision surgery, and better cosmetic outcomes.

Corrosion Analysis of an Experimental Noble Alloy on Commercially Pure Titanium Dental Implants

PubMed Central

Bortagaray, Manuel Alberto; Ibañez, Claudio Arturo Antonio; Ibañez, Maria Constanza; Ibañez, Juan Carlos

2016-01-01

Objective: To determine whether the Noble Bond® Argen® alloy was electrochemically suitable for the manufacturing of prosthetic superstructures over commercially pure titanium (c.p. Ti) implants. Also, the electrolytic corrosion effects over three types of materials used on prosthetic suprastructures that were coupled with titanium implants were analysed: Noble Bond® (Argen®), Argelite 76sf +® (Argen®), and commercially pure titanium. Materials and Methods: 15 samples were studied, consisting in 1 abutment and one c.p. titanium implant each. They were divided into three groups, namely: Control group: five c.p Titanium abutments (B&W®), Test group 1: five Noble Bond® (Argen®) cast abutments and, Test group 2: five Argelite 76sf +® (Argen®) abutments. In order to observe the corrosion effects, the surface topography was imaged using a confocal microscope. Thus, three metric parameters (Sa: Arithmetical mean height of the surface. Sp: Maximum height of peaks. Sv: Maximum height of valleys.), were measured at three different areas: abutment neck, implant neck and implant body. The samples were immersed in artificial saliva for 3 months, after which the procedure was repeated. The metric parameters were compared by statistical analysis. Results: The analysis of the Sa at the level of the implant neck, abutment neck and implant body, showed no statistically significant differences on combining c.p. Ti implants with the three studied alloys. The Sp showed no statistically significant differences between the three alloys. The Sv showed no statistically significant differences between the three alloys. Conclusion: The effects of electrogalvanic corrosion on each of the materials used when they were in contact with c.p. Ti showed no statistically significant differences. PMID:27733875

Correction of the significance level when attempting multiple transformations of an explanatory variable in generalized linear models

PubMed Central

2013-01-01

Background In statistical modeling, finding the most favorable coding for an exploratory quantitative variable involves many tests. This process involves multiple testing problems and requires the correction of the significance level. Methods For each coding, a test on the nullity of the coefficient associated with the new coded variable is computed. The selected coding corresponds to that associated with the largest statistical test (or equivalently the smallest pvalue). In the context of the Generalized Linear Model, Liquet and Commenges (Stat Probability Lett,71:33–38,2005) proposed an asymptotic correction of the significance level. This procedure, based on the score test, has been developed for dichotomous and Box-Cox transformations. In this paper, we suggest the use of resampling methods to estimate the significance level for categorical transformations with more than two levels and, by definition those that involve more than one parameter in the model. The categorical transformation is a more flexible way to explore the unknown shape of the effect between an explanatory and a dependent variable. Results The simulations we ran in this study showed good performances of the proposed methods. These methods were illustrated using the data from a study of the relationship between cholesterol and dementia. Conclusion The algorithms were implemented using R, and the associated CPMCGLM R package is available on the CRAN. PMID:23758852

Parametric and nonparametric Granger causality testing: Linkages between international stock markets

NASA Astrophysics Data System (ADS)

De Gooijer, Jan G.; Sivarajasingham, Selliah

2008-04-01

This study investigates long-term linear and nonlinear causal linkages among eleven stock markets, six industrialized markets and five emerging markets of South-East Asia. We cover the period 1987-2006, taking into account the on-set of the Asian financial crisis of 1997. We first apply a test for the presence of general nonlinearity in vector time series. Substantial differences exist between the pre- and post-crisis period in terms of the total number of significant nonlinear relationships. We then examine both periods, using a new nonparametric test for Granger noncausality and the conventional parametric Granger noncausality test. One major finding is that the Asian stock markets have become more internationally integrated after the Asian financial crisis. An exception is the Sri Lankan market with almost no significant long-term linear and nonlinear causal linkages with other markets. To ensure that any causality is strictly nonlinear in nature, we also examine the nonlinear causal relationships of VAR filtered residuals and VAR filtered squared residuals for the post-crisis sample. We find quite a few remaining significant bi- and uni-directional causal nonlinear relationships in these series. Finally, after filtering the VAR-residuals with GARCH-BEKK models, we show that the nonparametric test statistics are substantially smaller in both magnitude and statistical significance than those before filtering. This indicates that nonlinear causality can, to a large extent, be explained by simple volatility effects.

Blood lead level analysis among refugee children resettled in New Hampshire and Rhode Island.

PubMed

Raymond, Jaime S; Kennedy, Chinaro; Brown, Mary Jean

2013-01-01

To examine the association between refugee status and elevated blood lead levels (EBLLs) among children living in two U.S. cities and to assess the effect of the Centers for Disease Control and Prevention recommendations for BLL testing of newly emigrated refugee children for EBLLs. A longitudinal study was conducted of 1,007 refugee children and 953 nonrefugee children living, when blood testing occurred, in the same buildings in Manchester, New Hampshire and Providence, Rhode Island. Surveillance and blood lead data were collected from both sites, including demographic information, BLLs, sample type, refugee status, and age of housing. Refugee children living in Manchester were statistically significantly more likely to have an EBLL compared with nonrefugee children even after controlling for potential confounders. We did not find this association in Providence. Compared with before enactment, the mean time of refugee children to fall below 10 μg/dL was significantly shorter after the recommendations to test newly emigrated children were enacted. Refugee children living in Manchester were significantly more likely to have an EBLL compared with nonrefugee children. And among refugee children, we found a statistically significant difference in the mean days to BLL decline <10 μg/dL before and after recommendations to test newly emigrated children. © 2012 Wiley Periodicals, Inc.

[The problem of small "n" and big "P" in neuropsycho-pharmacology, or how to keep the rate of false discoveries under control].

PubMed

Petschner, Péter; Bagdy, György; Tóthfalusi, Laszló

2015-03-01

One of the characteristics of many methods used in neuropsychopharmacology is that a large number of parameters (P) are measured in relatively few subjects (n). Functional magnetic resonance imaging, electroencephalography (EEG) and genomic studies are typical examples. For example one microarray chip can contain thousands of probes. Therefore, in studies using microarray chips, P may be several thousand-fold larger than n. Statistical analysis of such studies is a challenging task and they are refereed to in the statistical literature such as the small "n" big "P" problem. The problem has many facets including the controversies associated with multiple hypothesis testing. A typical scenario in this context is, when two or more groups are compared by the individual attributes. If the increased classification error due to the multiple testing is neglected, then several highly significant differences will be discovered. But in reality, some of these significant differences are coincidental, not reproducible findings. Several methods were proposed to solve this problem. In this review we discuss two of the proposed solutions, algorithms to compare sets and statistical hypothesis tests controlling the false discovery rate.

DETECTING UNSPECIFIED STRUCTURE IN LOW-COUNT IMAGES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stein, Nathan M.; Dyk, David A. van; Kashyap, Vinay L.

Unexpected structure in images of astronomical sources often presents itself upon visual inspection of the image, but such apparent structure may either correspond to true features in the source or be due to noise in the data. This paper presents a method for testing whether inferred structure in an image with Poisson noise represents a significant departure from a baseline (null) model of the image. To infer image structure, we conduct a Bayesian analysis of a full model that uses a multiscale component to allow flexible departures from the posited null model. As a test statistic, we use a tailmore » probability of the posterior distribution under the full model. This choice of test statistic allows us to estimate a computationally efficient upper bound on a p-value that enables us to draw strong conclusions even when there are limited computational resources that can be devoted to simulations under the null model. We demonstrate the statistical performance of our method on simulated images. Applying our method to an X-ray image of the quasar 0730+257, we find significant evidence against the null model of a single point source and uniform background, lending support to the claim of an X-ray jet.« less

Emergence of patterns in random processes

NASA Astrophysics Data System (ADS)

Newman, William I.; Turcotte, Donald L.; Malamud, Bruce D.

2012-08-01

Sixty years ago, it was observed that any independent and identically distributed (i.i.d.) random variable would produce a pattern of peak-to-peak sequences with, on average, three events per sequence. This outcome was employed to show that randomness could yield, as a null hypothesis for animal populations, an explanation for their apparent 3-year cycles. We show how we can explicitly obtain a universal distribution of the lengths of peak-to-peak sequences in time series and that this can be employed for long data sets as a test of their i.i.d. character. We illustrate the validity of our analysis utilizing the peak-to-peak statistics of a Gaussian white noise. We also consider the nearest-neighbor cluster statistics of point processes in time. If the time intervals are random, we show that cluster size statistics are identical to the peak-to-peak sequence statistics of time series. In order to study the influence of correlations in a time series, we determine the peak-to-peak sequence statistics for the Langevin equation of kinetic theory leading to Brownian motion. To test our methodology, we consider a variety of applications. Using a global catalog of earthquakes, we obtain the peak-to-peak statistics of earthquake magnitudes and the nearest neighbor interoccurrence time statistics. In both cases, we find good agreement with the i.i.d. theory. We also consider the interval statistics of the Old Faithful geyser in Yellowstone National Park. In this case, we find a significant deviation from the i.i.d. theory which we attribute to antipersistence. We consider the interval statistics using the AL index of geomagnetic substorms. We again find a significant deviation from i.i.d. behavior that we attribute to mild persistence. Finally, we examine the behavior of Standard and Poor's 500 stock index's daily returns from 1928-2011 and show that, while it is close to being i.i.d., there is, again, significant persistence. We expect that there will be many other applications of our methodology both to interoccurrence statistics and to time series.

Communication skills in individuals with spastic diplegia.

PubMed

Lamônica, Dionísia Aparecida Cusin; Paiva, Cora Sofia Takaya; Abramides, Dagma Venturini Marques; Biazon, Jamile Lozano

2015-01-01

To assess communication skills in children with spastic diplegia. The study included 20 subjects, 10 preschool children with spastic diplegia and 10 typical matched according to gender, mental age, and socioeconomic status. Assessment procedures were the following: interviews with parents, Stanford - Binet method, Gross Motor Function Classification System, Observing the Communicative Behavior, Vocabulary Test by Peabody Picture, Denver Developmental Screening Test II, MacArthur Development Inventory on Communicative Skills. Statistical analysis was performed using the values of mean, median, minimum and maximum value, and using Student's t-test, Mann-Whitney test, and Paired t-test. Individuals with spastic diplegia, when compared to their peers of the same mental age, presented no significant difference in relation to receptive and expressive vocabulary, fine motor skills, adaptive, personal-social, and language. The most affected area was the gross motor skills in individuals with spastic cerebral palsy. The participation in intervention procedures and the pairing of participants according to mental age may have approximated the performance between groups. There was no statistically significant difference in the comparison between groups, showing appropriate communication skills, although the experimental group has not behaved homogeneously.

Changes in specialists' perspectives on cancer genetic testing, prophylactic surgery and insurance discrimination: then and now.

PubMed

Matloff, Ellen T; Bonadies, Danielle C; Moyer, Anne; Brierley, Karina L

2014-04-01

We surveyed cancer genetics specialists in 1998 to learn what they would do if at 50% risk to carry a BRCA or Lynch syndrome mutation. We chose to repeat our study 14 years later, to examine how perspectives have changed with the extensive data now available. In July 2012 we surveyed the National Society of Genetic Counselors (NSGC) Cancer Special Interest Group via an internet based survey. We found statistically significant increases in the percentage of specialists who: would undergo BRCA testing (p = 0.0006), opt for prophylactic bilateral mastectomy (p =0.0001), opt for prophylactic removal of their uterus and ovaries for Lynch syndrome (p =0.0057 and P = 0.0090, respectively), and bill testing to insurance (p >0.0001). There were also statistically significant decreases in the percentage of participants who would have their colon removed for Lynch syndrome (p = 0.0002) and use an alias when pursuing testing (p > 0.0001). Over the past 14 years there has been a major change in perspective amongst cancer genetic specialists regarding genetic testing, prophylactic surgery and insurance discrimination.

The thromboelastometric discrepancy between septic and trauma induced disseminated intravascular coagulation diagnosed by the scoring system from the Japanese association for acute medicine.

PubMed

Koami, Hiroyuki; Sakamoto, Yuichiro; Sakurai, Ryota; Ohta, Miho; Imahase, Hisashi; Yahata, Mayuko; Umeka, Mitsuru; Miike, Toru; Nagashima, Futoshi; Iwamura, Takashi; Yamada, Kosuke Chris; Inoue, Satoshi

2016-08-01

The aim of this study is to evaluate the hematological differences between septic and traumatic disseminated intravascular coagulation (DIC) using the rotational thromboelastometry (ROTEM).This retrospective study includes all sepsis or severe trauma patients transported to our emergency department who underwent ROTEM from 2013 to 2014. All patients were divided into 2 groups based on the presence of DIC diagnosed by the Japanese Association for Acute Medicine (JAAM) DIC score. We statistically analyzed the demographics, clinical characteristics, laboratory data, ROTEM findings (EXTEM and FIBTEM), and outcome.Fifty-seven patients (30 sepsis and 27 severe trauma) were included in primary analysis. Sepsis cases were significantly older and had higher systemic inflammatory response syndrome (SIRS) scores, whereas there were no significant differences in other parameters including Acute Physiology and Chronic Health Evaluation (APACHE) II score, sequential organ failure assessment (SOFA) score. Twenty-six patients (14 sepsis and 12 severe trauma) were diagnosed with DIC. The Septic DIC (S-DIC) group was significantly older and had higher DIC scores than the traumatic DIC (T-DIC) group. Hematologic examination revealed significantly higher CRP, fibrinogen, lower FDP, DD, and higher FDP/DD ratio were found in the S-DIC group in comparison with the T-DIC group. ROTEM findings showed that the A10, A20, and MCF in the FIBTEM test were significantly higher in the S-DIC group. However, no statistical differences were confirmed in the LI30, LI45, and ML in EXTEM test.The plasma fibrinogen level and fibrinogen based clot firmness in whole-blood test revealed statistical significance between septic and traumatic DIC patients.

A Comparison of Didactic and Inquiry Teaching Methods in a Rural Community College Earth Science Course

NASA Astrophysics Data System (ADS)

Beam, Margery Elizabeth

The combination of increasing enrollment and the importance of providing transfer students a solid foundation in science calls for science faculty to evaluate teaching methods in rural community colleges. The purpose of this study was to examine and compare the effectiveness of two teaching methods, inquiry teaching methods and didactic teaching methods, applied in a rural community college earth science course. Two groups of students were taught the same content via inquiry and didactic teaching methods. Analysis of quantitative data included a non-parametric ranking statistical testing method in which the difference between the rankings and the median of the post-test scores was analyzed for significance. Results indicated there was not a significant statistical difference between the teaching methods for the group of students participating in the research. The practical and educational significance of this study provides valuable perspectives on teaching methods and student learning styles in rural community colleges.

Mycoprotein reduces glycemia and insulinemia when taken with an oral-glucose-tolerance test.

PubMed

Turnbull, W H; Ward, T

1995-01-01

This study investigated the effects of mycoprotein, a food produced by the continuous fermentation of Fusarium graminearum (Schwabe), on acute glycemia and insulinemia in normal healthy individuals. Subjects participated in two single-meal study periods in a crossover design. After an overnight fast, subjects were given milkshakes containing mycoprotein or a control substance, which were isoenergetic and nutrient balanced. Each milkshake contained 75 g carbohydrate, equivalent to a standard World Health Organization oral-glucose-tolerance test. Blood samples were taken fasting and at 30, 60, 90, and 120 min postprandially for the measurement of serum glucose and insulin. Glycemia was reduced postmeal after mycoprotein compared with the control and was statistically significant at 60 min (13% reduction). Insulinemia was reduced postmeal after mycoprotein compared with the control and was statistically significant at 30 min (19% reduction) and 60 min (36% reduction) postmeal. These results may be significant in the dietary treatment of diabetes.

Oral versus intravenous paracetamol: which is better in closure of patent ductus arteriosus in very low birth weight infants?

PubMed

Sancak, Selim; Gokmen Yildirim, Tulin; Topcuoglu, Sevilay; Yavuz, Taner; Karatekin, Guner; Ovali, Fahri

2016-01-01

To compare the efficacy of oral and intravenous paracetamol for closure of hemodynamically significant patent ductus arteriosus (HSPDA) in very low birth weight (VLBW) preterm infants. Eighteen VLBW infants with HSPDA treated with either intravenous (n = 10) or oral (n = 8) paracetamol at 60 mg/kg/d for three consecutive days were analysed retrospectively. Ductal closure rate and evaluation of liver function tests were the major outcomes. After two courses of treatment, HSPDA closure rate was higher in oral paracetamol group than that in the intravenous paracetamol group (88% versus 70%), but it was not statistically significant (p = 0.588). Liver function tests were normal after the treatment. Although it was not statistically significant, the cumulative closure rates were higher in oral paracetamol group than those in the intravenous group. Larger trials are needed to confirm these data.

Co-Educational Tutorial Classes and Their Significance on Gendered Test Scores of Wollo University Students: A Before-After Analyses

ERIC Educational Resources Information Center

Gidey, Mu'uz

2015-01-01

This action research is carried out in a practical class room setting to devise an innovative way of administering tutorial classes to improve students' learning competence with particular reference to gendered test scores. A before-after test score analyses of mean and standard deviations along with t-statistical tests of hypotheses of second…

Validation of Survivability Validation Protocols

DTIC Science & Technology

1993-05-01

simu- lation fidelityl. Physical testing of P.i SOS, in either aboveground tests (AGTs) or underground test ( UGTs ), will usually be impossible, due...with some simulation fidelity compromises) are possible in UGTs and/orAGTs. Hence proof tests, if done in statistically significant numbers, can...level. Simulation fidelity and AGT/ UGT /threat correlation will be validation issues here. Extrapolation to threat environments will be done via modeling

Short-term effect of topical antiglaucoma medication on tear-film stability, tear secretion, and corneal sensitivity in healthy subjects.

PubMed

Terai, Naim; Müller-Holz, Matthias; Spoerl, Eberhard; Pillunat, Lutz E

2011-01-01

The purpose of this study was to investigate the short-term effect of topical antiglaucoma medication on tear-film stability, tear secretion, and corneal sensitivity in healthy subjects. In this prospective, double-blind crossover trial, break-up time and basal secretion (Jones test) were measured 60 minutes before, and 30, 60, and 90 minutes after topical antiglaucoma drop application in 30 healthy subjects. Corneal sensitivity was measured 60 minutes before, and five, 10, and 15 minutes after drop application using a Cochet-Bonnet esthesiometer. Reduction of break-up time in the latanoprost group was -23.8% after 30 minutes (P = 0.21), -26.7% after 60 minutes (P = 0.03) and -51.4% after 90 minutes (P ≤ 0.003), which was statistically significant. Reduction of break-up time in all other treatment groups was not statistically significant. The Jones test revealed a significant reduction of basal secretion after application of brimonidine (-17.8%, P = 0.002; -22.5%, P < 0.001; -30.5%, P < 0.001), followed by apraclonidine (-10%, P = 0.06; -20.1%, P = 0.02; -22.1%, P = 0.002), latanoprost (-2.4%, P = 0.64; -18.6%, P = 0.001; -20.1%, P = 0.001) and dorzolamide (-0.5%, P = 0.9; 14.3%, P = 0.018; -17.3%, P = 0.004) at 30, 60, and 90 minutes after drop application. Reduction of basal secretion in all other treatment groups was not statistically significant. Latanoprost showed the most statistically significant reduction in break-up time, and brimonidine showed the most significant reduction in basal secretion of all the glaucoma medications used in this study. In conclusion, our data may be helpful for treatment decisions in glaucoma patients who also suffer from ocular surface problems.

The distribution of P-values in medical research articles suggested selective reporting associated with statistical significance.

PubMed

Perneger, Thomas V; Combescure, Christophe

2017-07-01

Published P-values provide a window into the global enterprise of medical research. The aim of this study was to use the distribution of published P-values to estimate the relative frequencies of null and alternative hypotheses and to seek irregularities suggestive of publication bias. This cross-sectional study included P-values published in 120 medical research articles in 2016 (30 each from the BMJ, JAMA, Lancet, and New England Journal of Medicine). The observed distribution of P-values was compared with expected distributions under the null hypothesis (i.e., uniform between 0 and 1) and the alternative hypothesis (strictly decreasing from 0 to 1). P-values were categorized according to conventional levels of statistical significance and in one-percent intervals. Among 4,158 recorded P-values, 26.1% were highly significant (P < 0.001), 9.1% were moderately significant (P ≥ 0.001 to < 0.01), 11.7% were weakly significant (P ≥ 0.01 to < 0.05), and 53.2% were nonsignificant (P ≥ 0.05). We noted three irregularities: (1) high proportion of P-values <0.001, especially in observational studies, (2) excess of P-values equal to 1, and (3) about twice as many P-values less than 0.05 compared with those more than 0.05. The latter finding was seen in both randomized trials and observational studies, and in most types of analyses, excepting heterogeneity tests and interaction tests. Under plausible assumptions, we estimate that about half of the tested hypotheses were null and the other half were alternative. This analysis suggests that statistical tests published in medical journals are not a random sample of null and alternative hypotheses but that selective reporting is prevalent. In particular, significant results are about twice as likely to be reported as nonsignificant results. Copyright © 2017 Elsevier Inc. All rights reserved.

Child oral health-related quality of life and early childhood caries: a non-inferiority randomized control trial.

PubMed

Arrow, P; Klobas, E

2016-06-01

The aim of this study was to compare changes in child oral health-related quality of life (COHRQoL) after treatment for early childhood caries (ECC) using two alternative treatment approaches. A randomized control trial with random allocation of parent/child dyads with ECC to test (minimum intervention) or control (standard care). Participating parents completed the Early Childhood Oral Health Impact Scale (ECOHIS) at baseline and follow-up. Changes in ECOHIS scores and extent of COHRQoL impacts between and within groups were tested using the chi-squared statistic for groups, Wilcoxon's rank-sum test, and matched-pairs signed-rank test. Two hundred and fifty-four children were randomized (test = 127; control = 127). At baseline, mean ECOHIS score 11.1, sd 8.2; mean age = 3.8 years, sd 0.90; mean dmft = 4.9, sd 4.0; and 59% male. After a mean interval of 11.4 months, 210 children were followed-up and returned a completed questionnaire (test = 111; control = 99). There was no significant difference in COHRQoL changes between test and control. For all the children combined, there were significantly fewer impacts at follow-up in the child and family domains and the total ECOHIS, Wilcoxon signed-rank test, p < 0.05. COHRQoL improved with primary dental care for ECC, and there was no statistically significant difference between test and control in the extent of the improvement. © 2016 Australian Dental Association.

The influence of autocorrelation in signature extraction: An example from a geobotanical investigation of Cotter Basin, Montana

NASA Technical Reports Server (NTRS)

Labovitz, M. L.; Masuoka, E. J. (Principal Investigator)

1981-01-01

The presence of positive serial correlation (autocorrelation) in remotely sensed data results in an underestimate of the variance-covariance matrix when calculated using contiguous pixels. This underestimate produces an inflation in F statistics. For a set of Thematic Mapper Simulator data (TMS), used to test the ability to discriminate a known geobotanical anomaly from its background, the inflation in F statistics related to serial correlation is between 7 and 70 times. This means that significance tests of means of the spectral bands initially appear to suggest that the anomalous site is very different in spectral reflectance and emittance from its background sites. However, this difference often disappears and is always dramatically reduced when compared to frequency distributions of test statistics produced by the comparison of simulated training sets possessing equal means, but which are composed of autocorrelated observations.

The Differential Effect of Sustained Operations on Psychomotor Skills of Helicopter Pilots.

PubMed

McMahon, Terry W; Newman, David G

2018-06-01

Flying a helicopter is a complex psychomotor skill requiring constant control inputs from pilots. A deterioration in psychomotor performance of a helicopter pilot may be detrimental to operational safety. The aim of this study was to test the hypothesis that psychomotor performance deteriorates over time during sustained operations and that the effect is more pronounced in the feet than the hands. The subjects were helicopter pilots conducting sustained multicrew offshore flight operations in a demanding environment. The remote flight operations involved constant workload in hot environmental conditions with complex operational tasking. Over a period of 6 d 10 helicopter pilots were tested. At the completion of daily flying duties, a helicopter-specific screen-based compensatory tracking task measuring tracking accuracy (over a 5-min period) tested both hands and feet. Data were compared over time and tested for statistical significance for both deterioration and differential effect. A statistically significant deterioration of psychomotor performance was evident in the pilots over time for both hands and feet. There was also a statistically significant differential effect between the hands and the feet in terms of tracking accuracy. The hands recorded a 22.6% decrease in tracking accuracy, while the feet recorded a 39.9% decrease in tracking accuracy. The differential effect may be due to prioritization of limb movement by the motor cortex due to factors such as workload-induced cognitive fatigue. This may result in a greater reduction in performance in the feet than the hands, posing a significant risk to operational safety.McMahon TW, Newman DG. The differential effect of sustained operations on psychomotor skills of helicopter pilots. Aerosp Med Hum Perform. 2018; 89(6):496-502.

Settling of abutments into implants and changes in removal torque in five different implant-abutment connections. Part 1: Cyclic loading.

PubMed

Kim, Ki-Seong; Han, Jung-Suk; Lim, Young-Jun

2014-01-01

The aim of this study was to evaluate and compare the settling of abutments into implants and the removal torque values (RTVs) before and after cyclic loading. Five different implant-abutment connections were tested: Ext = external butt joint + two-piece abutment; Int-H2 = internal hexagon + two-piece abutment; Int-H1 = internal hexagon + one-piece abutment; Int-O2 = internal octagon + two-piece abutment; and Int-O1 = internal octagon + one-piece abutment. Ten abutments from each group were secured to their corresponding implants (total n = 50). All samples were tested in a universal testing machine with a vertical load of 250 N for 100,000 cycles of 14 Hz. The amount of settling of the abutment into the implant was calculated from the change in the total length of the implant-abutment sample before and after loading, as measured with an electronic digital micrometer. The RTV after cyclic loading was compared to the initial RTV with a digital torque gauge. Statistical analysis was performed at a 5% significance level. A multiple-comparison test showed specific significant differences in settling values in each group after 250 N cyclic loading (Int-H1, Ext < Int-H2 < Int-O2 < Int-O1). There were statistically significant decreases in RTVs after loading compared to the initial RTVs in the Int-H2 and Int-O2 groups. No statistically significant differences were found in the Ext, Int-H1, and Int-O1 groups. The results of this study demonstrated that the settling amount and RTV (loss of preload) after cyclic loading were specific to the abutment type and related to the design characteristics of the implant-abutment connection.

Effect of a Trampoline Exercise on the Anthropometric Measures and Motor Performance of Adolescent Students

PubMed Central

Aalizadeh, Bahman; Mohammadzadeh, Hassan; Khazani, Ali; Dadras, Ali

2016-01-01

Background: Physical exercises can influence some anthropometric and fitness components differently. The aim of present study was to evaluate how a relatively long-term training program in 11-14-year-old male Iranian students affects their anthropometric and motor performance measures. Methods: Measurements were conducted on the anthropometric and fitness components of participants (n = 28) prior to and following the program. They trained 20 weeks, 1.5 h/session with 10 min rest, in 4 times trampoline training programs per week. Motor performance of all participants was assessed using standing long jump and vertical jump based on Eurofit Test Battery. Results: The analysis of variance (ANOVA) repeated measurement test showed a statistically significant main effect of time in calf girth P = 0.001, fat% P = 0.01, vertical jump P = 0.001, and long jump P = 0.001. The ANOVA repeated measurement test revealed a statistically significant main effect of group in fat% P = 0.001. Post hoc paired t-tests indicated statistical significant differences in trampoline group between the two measurements about calf girth (t = −4.35, P = 0.001), fat% (t = 5.87, P = 0.001), vertical jump (t = −5.53, P = 0.001), and long jump (t = −10.00, P = 0.001). Conclusions: We can conclude that 20-week trampoline training with four physical activity sessions/week in 11–14-year-old students seems to have a significant effect on body fat% reduction and effective results in terms of anaerobic physical fitness. Therefore, it is suggested that different training model approach such as trampoline exercises can help students to promote the level of health and motor performance. PMID:27512557

Effect of a Trampoline Exercise on the Anthropometric Measures and Motor Performance of Adolescent Students.

PubMed

Aalizadeh, Bahman; Mohammadzadeh, Hassan; Khazani, Ali; Dadras, Ali

2016-01-01

Physical exercises can influence some anthropometric and fitness components differently. The aim of present study was to evaluate how a relatively long-term training program in 11-14-year-old male Iranian students affects their anthropometric and motor performance measures. Measurements were conducted on the anthropometric and fitness components of participants (n = 28) prior to and following the program. They trained 20 weeks, 1.5 h/session with 10 min rest, in 4 times trampoline training programs per week. Motor performance of all participants was assessed using standing long jump and vertical jump based on Eurofit Test Battery. The analysis of variance (ANOVA) repeated measurement test showed a statistically significant main effect of time in calf girth P = 0.001, fat% P = 0.01, vertical jump P = 0.001, and long jump P = 0.001. The ANOVA repeated measurement test revealed a statistically significant main effect of group in fat% P = 0.001. Post hoc paired t-tests indicated statistical significant differences in trampoline group between the two measurements about calf girth (t = -4.35, P = 0.001), fat% (t = 5.87, P = 0.001), vertical jump (t = -5.53, P = 0.001), and long jump (t = -10.00, P = 0.001). We can conclude that 20-week trampoline training with four physical activity sessions/week in 11-14-year-old students seems to have a significant effect on body fat% reduction and effective results in terms of anaerobic physical fitness. Therefore, it is suggested that different training model approach such as trampoline exercises can help students to promote the level of health and motor performance.

Statistical power to detect violation of the proportional hazards assumption when using the Cox regression model.

PubMed

Austin, Peter C

2018-01-01

The use of the Cox proportional hazards regression model is widespread. A key assumption of the model is that of proportional hazards. Analysts frequently test the validity of this assumption using statistical significance testing. However, the statistical power of such assessments is frequently unknown. We used Monte Carlo simulations to estimate the statistical power of two different methods for detecting violations of this assumption. When the covariate was binary, we found that a model-based method had greater power than a method based on cumulative sums of martingale residuals. Furthermore, the parametric nature of the distribution of event times had an impact on power when the covariate was binary. Statistical power to detect a strong violation of the proportional hazards assumption was low to moderate even when the number of observed events was high. In many data sets, power to detect a violation of this assumption is likely to be low to modest.

Statistical power to detect violation of the proportional hazards assumption when using the Cox regression model

PubMed Central

Austin, Peter C.

2017-01-01

The use of the Cox proportional hazards regression model is widespread. A key assumption of the model is that of proportional hazards. Analysts frequently test the validity of this assumption using statistical significance testing. However, the statistical power of such assessments is frequently unknown. We used Monte Carlo simulations to estimate the statistical power of two different methods for detecting violations of this assumption. When the covariate was binary, we found that a model-based method had greater power than a method based on cumulative sums of martingale residuals. Furthermore, the parametric nature of the distribution of event times had an impact on power when the covariate was binary. Statistical power to detect a strong violation of the proportional hazards assumption was low to moderate even when the number of observed events was high. In many data sets, power to detect a violation of this assumption is likely to be low to modest. PMID:29321694

Dental Composite Restorations and Neuropsychological Development in Children: Treatment Level Analysis from a Randomized Clinical Trial

PubMed Central

Maserejian, Nancy N.; Trachtenberg, Felicia L.; Hauser, Russ; McKinlay, Sonja; Shrader, Peter; Bellinger, David C.

2012-01-01

Background Resin-based dental restorations may intra-orally release their components and bisphenol A. Gestational bisphenol A exposure has been associated with poorer executive functioning in children. Objectives To examine whether exposure to resin-based composite restorations is associated with neuropsychological development in children. Methods Secondary analysis of treatment level data from the New England Children’s Amalgam Trial, a 2-group randomized safety trial conducted from 1997–2006. Children (N=534) aged 6–10 y with >2 posterior tooth caries were randomized to treatment with amalgam or resin-based composites (bisphenol-A-diglycidyl-dimethacrylate-composite for permanent teeth; urethane dimethacrylate-based polyacid-modified compomer for primary teeth). Neuropsychological function at 4- and 5-year follow-up (N=444) was measured by a battery of tests of executive function, intelligence, memory, visual-spatial skills, verbal fluency, and problem-solving. Multivariable generalized linear regression models were used to examine the association between composite exposure levels and changes in neuropsychological test scores from baseline to follow-up. For comparison, data on children randomized to amalgam treatment were similarly analyzed. Results With greater exposure to either dental composite material, results were generally consistent in the direction of slightly poorer changes in tests of intelligence, achievement or memory, but there were no statistically significant associations. For the four primary measures of executive function, scores were slightly worse with greater total composite exposure, but statistically significant only for the test of Letter Fluency (10-surface-years β= −0.8, SE=0.4, P=0.035), and the subtest of color naming (β= −1.5, SE=0.5, P=0.004) in the Stroop Color-Word Interference Test. Multivariate analysis of variance confirmed that the negative associations between composite level and executive function were not statistically significant (MANOVA P=0.18). Results for greater amalgam exposure were mostly nonsignificant in the opposite direction of slightly improved scores over follow-up. Conclusions Dental composite restorations had statistically insignificant associations of small magnitude with impairments in neuropsychological test change scores over 4- or 5-years of follow-up in this trial. PMID:22906860

High Impact = High Statistical Standards? Not Necessarily So

PubMed Central

Tressoldi, Patrizio E.; Giofré, David; Sella, Francesco; Cumming, Geoff

2013-01-01

What are the statistical practices of articles published in journals with a high impact factor? Are there differences compared with articles published in journals with a somewhat lower impact factor that have adopted editorial policies to reduce the impact of limitations of Null Hypothesis Significance Testing? To investigate these questions, the current study analyzed all articles related to psychological, neuropsychological and medical issues, published in 2011 in four journals with high impact factors: Science, Nature, The New England Journal of Medicine and The Lancet, and three journals with relatively lower impact factors: Neuropsychology, Journal of Experimental Psychology-Applied and the American Journal of Public Health. Results show that Null Hypothesis Significance Testing without any use of confidence intervals, effect size, prospective power and model estimation, is the prevalent statistical practice used in articles published in Nature, 89%, followed by articles published in Science, 42%. By contrast, in all other journals, both with high and lower impact factors, most articles report confidence intervals and/or effect size measures. We interpreted these differences as consequences of the editorial policies adopted by the journal editors, which are probably the most effective means to improve the statistical practices in journals with high or low impact factors. PMID:23418533

High impact  =  high statistical standards? Not necessarily so.

PubMed

Tressoldi, Patrizio E; Giofré, David; Sella, Francesco; Cumming, Geoff

2013-01-01

What are the statistical practices of articles published in journals with a high impact factor? Are there differences compared with articles published in journals with a somewhat lower impact factor that have adopted editorial policies to reduce the impact of limitations of Null Hypothesis Significance Testing? To investigate these questions, the current study analyzed all articles related to psychological, neuropsychological and medical issues, published in 2011 in four journals with high impact factors: Science, Nature, The New England Journal of Medicine and The Lancet, and three journals with relatively lower impact factors: Neuropsychology, Journal of Experimental Psychology-Applied and the American Journal of Public Health. Results show that Null Hypothesis Significance Testing without any use of confidence intervals, effect size, prospective power and model estimation, is the prevalent statistical practice used in articles published in Nature, 89%, followed by articles published in Science, 42%. By contrast, in all other journals, both with high and lower impact factors, most articles report confidence intervals and/or effect size measures. We interpreted these differences as consequences of the editorial policies adopted by the journal editors, which are probably the most effective means to improve the statistical practices in journals with high or low impact factors.

Evaluation of surface detail reproduction, dimensional stability and gypsum compatibility of monophase polyvinyl-siloxane and polyether elastomeric impression materials under dry and moist conditions

PubMed Central

Vadapalli, Sriharsha Babu; Atluri, Kaleswararao; Putcha, Madhu Sudhan; Kondreddi, Sirisha; Kumar, N. Suman; Tadi, Durga Prasad

2016-01-01

Objectives: This in vitro study was designed to compare polyvinyl-siloxane (PVS) monophase and polyether (PE) monophase materials under dry and moist conditions for properties such as surface detail reproduction, dimensional stability, and gypsum compatibility. Materials and Methods: Surface detail reproduction was evaluated using two criteria. Dimensional stability was evaluated according to American Dental Association (ADA) specification no. 19. Gypsum compatibility was assessed by two criteria. All the samples were evaluated, and the data obtained were analyzed by a two-way analysis of variance (ANOVA) and Pearson's Chi-square tests. Results: When surface detail reproduction was evaluated with modification of ADA specification no. 19, both the groups under the two conditions showed no significant difference statistically. When evaluated macroscopically both the groups showed statistically significant difference. Results for dimensional stability showed that the deviation from standard was significant among the two groups, where Aquasil group showed significantly more deviation compared to Impregum group (P < 0.001). Two conditions also showed significant difference, with moist conditions showing significantly more deviation compared to dry condition (P < 0.001). The results of gypsum compatibility when evaluated with modification of ADA specification no. 19 and by giving grades to the casts for both the groups and under two conditions showed no significant difference statistically. Conclusion: Regarding dimensional stability, both impregum and aquasil performed better in dry condition than in moist; impregum performed better than aquasil in both the conditions. When tested for surface detail reproduction according to ADA specification, under dry and moist conditions both of them performed almost equally. When tested according to macroscopic evaluation, impregum and aquasil performed significantly better in dry condition compared to moist condition. In dry condition, both the materials performed almost equally. In moist condition, aquasil performed significantly better than impregum. Regarding gypsum compatibility according to ADA specification, in dry condition both the materials performed almost equally, and in moist condition aquasil performed better than impregum. When tested by macroscopic evaluation, impregum performed better than aquasil in both the conditions. PMID:27583217

Evaluation of surface detail reproduction, dimensional stability and gypsum compatibility of monophase polyvinyl-siloxane and polyether elastomeric impression materials under dry and moist conditions.

PubMed

Vadapalli, Sriharsha Babu; Atluri, Kaleswararao; Putcha, Madhu Sudhan; Kondreddi, Sirisha; Kumar, N Suman; Tadi, Durga Prasad

2016-01-01

This in vitro study was designed to compare polyvinyl-siloxane (PVS) monophase and polyether (PE) monophase materials under dry and moist conditions for properties such as surface detail reproduction, dimensional stability, and gypsum compatibility. Surface detail reproduction was evaluated using two criteria. Dimensional stability was evaluated according to American Dental Association (ADA) specification no. 19. Gypsum compatibility was assessed by two criteria. All the samples were evaluated, and the data obtained were analyzed by a two-way analysis of variance (ANOVA) and Pearson's Chi-square tests. When surface detail reproduction was evaluated with modification of ADA specification no. 19, both the groups under the two conditions showed no significant difference statistically. When evaluated macroscopically both the groups showed statistically significant difference. Results for dimensional stability showed that the deviation from standard was significant among the two groups, where Aquasil group showed significantly more deviation compared to Impregum group (P < 0.001). Two conditions also showed significant difference, with moist conditions showing significantly more deviation compared to dry condition (P < 0.001). The results of gypsum compatibility when evaluated with modification of ADA specification no. 19 and by giving grades to the casts for both the groups and under two conditions showed no significant difference statistically. Regarding dimensional stability, both impregum and aquasil performed better in dry condition than in moist; impregum performed better than aquasil in both the conditions. When tested for surface detail reproduction according to ADA specification, under dry and moist conditions both of them performed almost equally. When tested according to macroscopic evaluation, impregum and aquasil performed significantly better in dry condition compared to moist condition. In dry condition, both the materials performed almost equally. In moist condition, aquasil performed significantly better than impregum. Regarding gypsum compatibility according to ADA specification, in dry condition both the materials performed almost equally, and in moist condition aquasil performed better than impregum. When tested by macroscopic evaluation, impregum performed better than aquasil in both the conditions.

Comparison of antibacterial activity of Talok (Muntingia calabura L) leaves ethanolic and n-hexane extracts on Propionibacterium acnes

NASA Astrophysics Data System (ADS)

Desrini, Sufi; Ghiffary, Hifzhan Maulana

2018-04-01

Muntingia calabura L., also known locally as Talok or Kersen, is a plant which has been widely used as traditional medicine in Indonesia. In this study, we evaluated the antibacterial activity of Muntingia calabura L. Leaves ethanolic and n-hexane extract extract on Propionibacterium acnes. Antibacterial activity was determined in the extracts using agar well diffusion method. The antibacterial activities of each extract (2 mg/mL, 8 mg/ml, 20 mg/mL 30 mg/mL, and 40 mg/mL) were tested against to Propionibacterium acnes. Zone of inhibition of ethanolic extract and n-hexane extract was measured, compared, and analyzed by using a statistical programme. The phytochemical analyses of the plants were carried out using thin chromatography layer (TLC). The average diameter zone of inhibition at the concentration of 2 mg/mL of the ethanolic extract is 9,97 mm while n-Hexane extract at the same concentration showed 0 mm. Statistical test used was non-parametric test using Kruskal Wallis test which was continued to the Mann-Whitney to see the magnitude of the difference between concentration among groups. Kruskal-Wallis test revealed a significant value 0,000. Based on the result of Post Hoc test using Mann - Whitney test, there is the statistically significant difference between each concentration of ethanolic extract and n-hexane as well as positive control group (p-value < 0,05). Both extracts have antibacterial activity on P.acne. However, ethanolic extract of Muntingia calabura L. is better in inhibiting Propionibacterium acnes growth than n-hexane extract.

The results of STEM education methods for enhancing critical thinking and problem solving skill in physics the 10th grade level

NASA Astrophysics Data System (ADS)

Soros, P.; Ponkham, K.; Ekkapim, S.

2018-01-01

This research aimed to: 1) compare the critical think and problem solving skills before and after learning using STEM Education plan, 2) compare student achievement before and after learning about force and laws of motion using STEM Education plan, and 3) the satisfaction of learning by using STEM Education. The sample used were 37 students from grade 10 at Borabu School, Borabu District, Mahasarakham Province, semester 2, Academic year 2016. Tools used in this study consist of: 1) STEM Education plan about the force and laws of motion for grade 10 students of 1 schemes with total of 14 hours, 2) The test of critical think and problem solving skills with multiple-choice type of 5 options and 2 option of 30 items, 3) achievement test on force and laws of motion with multiple-choice of 4 options of 30 items, 4) satisfaction learning with 5 Rating Scale of 20 items. The statistics used in data analysis were percentage, mean, standard deviation, and t-test (Dependent). The results showed that 1) The student with learning using STEM Education plan have score of critical think and problem solving skills on post-test higher than pre-test with statistically significant level .01. 2) The student with learning using STEM Education plan have achievement score on post-test higher than pre-test with statistically significant level of .01. 3) The student'level of satisfaction toward the learning by using STEM Education plan was at a high level (X ¯ = 4.51, S.D=0.56).

LandScape: a simple method to aggregate p-values and other stochastic variables without a priori grouping.

PubMed

Wiuf, Carsten; Schaumburg-Müller Pallesen, Jonatan; Foldager, Leslie; Grove, Jakob

2016-08-01

In many areas of science it is custom to perform many, potentially millions, of tests simultaneously. To gain statistical power it is common to group tests based on a priori criteria such as predefined regions or by sliding windows. However, it is not straightforward to choose grouping criteria and the results might depend on the chosen criteria. Methods that summarize, or aggregate, test statistics or p-values, without relying on a priori criteria, are therefore desirable. We present a simple method to aggregate a sequence of stochastic variables, such as test statistics or p-values, into fewer variables without assuming a priori defined groups. We provide different ways to evaluate the significance of the aggregated variables based on theoretical considerations and resampling techniques, and show that under certain assumptions the FWER is controlled in the strong sense. Validity of the method was demonstrated using simulations and real data analyses. Our method may be a useful supplement to standard procedures relying on evaluation of test statistics individually. Moreover, by being agnostic and not relying on predefined selected regions, it might be a practical alternative to conventionally used methods of aggregation of p-values over regions. The method is implemented in Python and freely available online (through GitHub, see the Supplementary information).

Comparative clinical evaluation of coronally advanced flap with or without platelet rich fibrin membrane in the treatment of isolated gingival recession

PubMed Central

Thamaraiselvan, Murugan; Elavarasu, Sugumari; Thangakumaran, Suthanthiran; Gadagi, Jayaprakash Sharanabasappa; Arthie, Thangavelu

2015-01-01

Aim: The aim of this study was to determine whether the addition of an autologous platelet rich fibrin (PRF) membrane to a coronally advanced flap (CAF) would improve the clinical outcome in terms of root coverage, in the treatment of isolated gingival recession. Materials and Methods: Systemically healthy 20 subjects each with single Miller's class I or II buccal recession defect were randomly assigned to control (CAF) or test (CAF + PRF) group. Clinical outcome was determined by measuring the following clinical parameters such as recession depth (RD), recession width (RW), probing depth (PD), clinical attachment level (CAL), width of keratinized tissue (WKT), gingival thickness (GTH), plaque index (PI), and gingival index (GI) at baseline, 3rd, and 6th month postsurgery. Results: The root coverage was 65.00 ± 44.47% in the control group and 74.16 ± 28.98% in the test group at 6th month, with no statistically significant difference between them. Similarly, CAL, PD, and WKT between the groups were not statistically significant. Conversely, there was statistically significant increase in GTH in the test group. Conclusion: CAF is a predictable treatment for isolated Miller's class I and II recession defects. The addition of PRF to CAF provided no added advantage in terms of root coverage except for an increase in GTH. PMID:25810596

Silent myocardial ischaemia: the Tan Tock Seng experience.

PubMed

Mak, K H; Tan, E K; Chew, L; Gan, S H; Chan, A L

1991-10-01

The results of treadmill exercise stress test (TMX) for ischaemia is based on ST-segment depression. Patients with positive test may or may not be symptomatic. This study examines if there are any differences between these two groups of patients. A total of thirty-nine patients with coronary artery disease and positive TMX results in 1988 was studied. There were 16 patients with chest pain and 23 without. They were followed-up for a mean period of 16.9 and 15.2 months respectively. The following factors were found not to be statistically significant between these two groups of patients: age, sex, race, height, weight, history of hypertension, diabetes mellitus or smoking, indication for the test, use of drugs, total and HDL-cholesterol, exercise duration and the initial double product. The difference between the maximal double product of the two groups was statistically significant (p = 0.004). In the follow-up period, in the group of patients with silent myocardial ischaemia, one had a cardiac event and one underwent revascularisation. While in the symptomatic group, two had cardiac events and seven underwent revascularisation. There were no deaths in either group. The difference in overall outcome was significant statistically (p = 0.002). Therefore, patients with silent myocardial ischaemia have a higher maximal double product in TMX; hence a higher maximal workload and a less adverse outcome compared to symptomatic patients.

Randomized controlled trial of toothbrushing to reduce ventilator-associated pneumonia pathogens and dental plaque in a critical care unit.

PubMed

Needleman, Ian G; Hirsch, Nicholas P; Leemans, Michele; Moles, David R; Wilson, Michael; Ready, Derren R; Ismail, Salim; Ciric, Lena; Shaw, Michael J; Smith, Martin; Garner, Anne; Wilson, Sally

2011-03-01

To investigate the effect of a powered toothbrush on colonization of dental plaque by ventilator-associated pneumonia (VAP)-associated organisms and dental plaque removal. Parallel-arm, single-centre, examiner- and analyst-masked randomized controlled trial. Forty-six adults were recruited within 48 h of admission. Test intervention: powered toothbrush, control intervention: sponge toothette, both used four times per day for 2 min. Groups received 20 ml, 0.2% chlorhexidine mouthwash at each time point. The results showed a low prevalence of respiratory pathogens throughout with no statistically significant differences between groups. A highly statistically significantly greater reduction in dental plaque was produced by the powered toothbrush compared with the control treatment; mean plaque index at day 5, powered toothbrush 0.75 [95% confidence interval (CI) 0.53, 1.00], sponge toothette 1.35 (95% CI 0.95, 1.74), p=0.006. Total bacterial viable count was also highly statistically significantly lower in the test group at day 5; Log(10) mean total bacterial counts: powered toothbrush 5.12 (95% CI 4.60, 5.63), sponge toothette 6.61 (95% CI 5.93, 7.28), p=0.002. Powered toothbrushes are highly effective for plaque removal in intubated patients in a critical unit and should be tested for their potential to reduce VAP incidence and health complications. © 2011 John Wiley & Sons A/S.

Investigation of the potential carcinogenicity of a range of chromium containing materials on rat lung.

PubMed Central

Levy, L S; Martin, P A; Bidstrup, P L

1986-01-01

Twenty one chromium containing materials were examined for carcinogenic activity in a two year study using an intrabronchial pellet implantation system whereby pellets loaded with test material were surgically implanted into the lower left bronchus of rats. The principal aim of the study was to extend our knowledge of the carcinogenic potential of chromium compounds and, in particular, chromates (Cr6+). A statistically significant incidence of treatment related lung tumours was found with some sparingly soluble chromate materials. All tumours were large keratinizing squamous carcinomas of the left lung, except for a single left lung adenocarcinoma and two left lung anaplastic carcinomas. No bronchial carcinomas (0/100) were seen in the negative control group (blank pellet loaded with cholesterol), whereas bronchial carcinomas (22/48 and 25/100) occurred in the two positive control groups which received pellets loaded with 20-methylcholanthrene and calcium chromate respectively. Among the 20 test materials, only three groups gave statistically significant numbers of bronchial carcinomas. Two of these were groups receiving different samples of strontium chromate which gave 43/99 and 62/99 tumours. The third group, zinc chromate (low solubility), gave 5/100 bronchial carcinomas. A further zinc chromate group (Norge composition) produced 3/100 bronchial carcinomas which was not statistically significant. A few lung tumours were observed in other test groups. Images PMID:3964573

Average ambulatory measures of sound pressure level, fundamental frequency, and vocal dose do not differ between adult females with phonotraumatic lesions and matched control subjects

PubMed Central

Van Stan, Jarrad H.; Mehta, Daryush D.; Zeitels, Steven M.; Burns, James A.; Barbu, Anca M.; Hillman, Robert E.

2015-01-01

Objectives Clinical management of phonotraumatic vocal fold lesions (nodules, polyps) is based largely on assumptions that abnormalities in habitual levels of sound pressure level (SPL), fundamental frequency (f0), and/or amount of voice use play a major role in lesion development and chronic persistence. This study used ambulatory voice monitoring to evaluate if significant differences in voice use exist between patients with phonotraumatic lesions and normal matched controls. Methods Subjects were 70 adult females: 35 with vocal fold nodules or polyps and 35 age-, sex-, and occupation-matched normal individuals. Weeklong summary statistics of voice use were computed from anterior neck surface acceleration recorded using a smartphone-based ambulatory voice monitor. Results Paired t-tests and Kolmogorov-Smirnov tests resulted in no statistically significant differences between patients and matched controls regarding average measures of SPL, f0, vocal dose measures, and voicing/voice rest periods. Paired t-tests comparing f0 variability between the groups resulted in statistically significant differences with moderate effect sizes. Conclusions Individuals with phonotraumatic lesions did not exhibit differences in average ambulatory measures of vocal behavior when compared with matched controls. More refined characterizations of underlying phonatory mechanisms and other potentially contributing causes are warranted to better understand risk factors associated with phonotraumatic lesions. PMID:26024911

p63 and Ki-67 immunostainings in laryngeal squamous cell carcinoma are related to survival.

PubMed

Re, M; Zizzi, A; Ferrante, L; Stramazzotti, D; Goteri, G; Gioacchini, F M; Olivieri, F; Magliulo, G; Rubini, C

2014-06-01

To examine the prognostic significance of the immunohistochemical expression of p63 and Ki-67 oncoproteins in patients with laryngeal squamous cell carcinoma, a retrospective evaluation was carried out on a cohort of 108 patients with primary laryngeal squamous cell carcinoma (LSCC) treated by primary surgery. For the immunohistochemical evaluation, tissue section obtained by formalin-fixed and paraffin-embedded tissue blocks from resection of each patient was used. Clinicopathologic data were associated with the immunostaining results. The association among the considered variables was assessed by Fisher's exact test, Mann-Whitney test, non-parametric χ(2) test, and Spearman's rho rank test was used to assess the relations among them. Differences in p63 and Ki-67 immunoreactivity among the different groups were compared via Kruskal-Wallis test and post hoc tests were performed using Mann-Whitney test with Bonferroni correction. The overall survival rate was estimated via Kaplan-Meier method, and the cumulative incidence functions for different groups were compared using log-rank statistics. Cox proportional hazard model was employed in a multivariate analysis to assess the effect of prognostic factors in the overall survival rate. Furthermore, taking into account death due to other causes, we estimated LSCC-related survival and disease-free survival rates using competing risk analysis. The results of immunohistochemical examination showed a statistically significant relationship between the up-regulation of P63 and Ki-67, an increase in histological grading, and primary tumours associated with lymph node metastases. p63 and Ki-67 up-regulation was related to a shorter disease-free survival and a significant association was found between p63 and Ki-67 percentage of positive cells and patient survival. Finally, we noticed a significant relation between p63 and Ki-67 (ρ = 0.87). On the other hand, no statistically significant associations were found between p63 and Ki-67 down-regulation and clinicopathologic data. Our findings suggest that abnormal p63 and Ki-67 immunoreactivity may be involved in the early phases of laryngeal tumorigenesis and may become a significant prognostic predictor for both overall and disease-free survivals. These biomarkers could thus help in the selection of high-risk patients with LSCC who may benefit from more aggressive therapy or chemoprevention.

Empirical study of alginate impression materials by customized proportioning system

PubMed Central

2016-01-01

PURPOSE Alginate mixers available in the market do not have the automatic proportioning unit. In this study, an automatic proportioning unit for the alginate mixer and controller software were designed and produced for a new automatic proportioning unit. With this device, it was ensured that proportioning operation could arrange weight-based alginate impression materials. MATERIALS AND METHODS The variation of coefficient in the tested groups was compared with the manual proportioning. Compression tension and tear tests were conducted to determine the mechanical properties of alginate impression materials. The experimental data were statistically analyzed using one way ANOVA and Tukey test at the 0.05 level of significance. RESULTS No statistically significant differences in modulus of elastisity (P>0.3), tensional/compresional strength (P>0.3), resilience (P>0.2), strain in failure (P>0.4), and tear energy (P>0.7) of alginate impression materials were seen. However, a decrease in the standard deviation of tested groups was observed when the customized machine was used. To verify the efficiency of the system, powder and powder/water mixing were weighed and significant decrease was observed. CONCLUSION It was possible to obtain more mechanically stable alginate impression materials by using the custom-made proportioning unit. PMID:27826387

Differences of Cytotoxicity of Orthodontic Bands Assessed by Survival Tests in Saccharomyces cerevisiae

PubMed Central

Gonçalves, Tatiana Siqueira; de Menezes, Luciane Macedo; Ribeiro, Luciele Gonzaga; Lindholz, Catieli Gobetti; Medina-Silva, Renata

2014-01-01

The aim of this study was to evaluate the cytotoxicity induced by orthodontic bands through survival tests on Saccharomyces cerevisiae, a microorganism that presents several genetic and biochemical characteristics similar to human cells. Three groups of bands were evaluated: silver soldered (SSB), laser soldered (LSB), and bands without any solder (WSB). Yeast cells were directly exposed to the bands and indirectly, when a previous elution of the metals in artificial saliva was performed. The negative control was composed of yeast cells or artificial saliva not exposed to any kind of metal. In the direct exposure experiments, all tested groups of bands induced a slight reduction in yeast viability compared to the control. This effect was more intense for the SSB, although not statistically significant. For the indirect exposure experiments, the SSB induced a statistically significant decrease in cell viability compared to the LSB. There were no significant differences between the survival rates of the negative control and the LSB group in both direct and saliva tests. SSBs were cytotoxic, whilst LSBs were not, confirming that laser soldering may be a more biocompatible alternative for use in connecting wires to orthodontic appliances. PMID:24511527

SOCR Analyses – an Instructional Java Web-based Statistical Analysis Toolkit

PubMed Central

Chu, Annie; Cui, Jenny; Dinov, Ivo D.

2011-01-01

The Statistical Online Computational Resource (SOCR) designs web-based tools for educational use in a variety of undergraduate courses (Dinov 2006). Several studies have demonstrated that these resources significantly improve students' motivation and learning experiences (Dinov et al. 2008). SOCR Analyses is a new component that concentrates on data modeling and analysis using parametric and non-parametric techniques supported with graphical model diagnostics. Currently implemented analyses include commonly used models in undergraduate statistics courses like linear models (Simple Linear Regression, Multiple Linear Regression, One-Way and Two-Way ANOVA). In addition, we implemented tests for sample comparisons, such as t-test in the parametric category; and Wilcoxon rank sum test, Kruskal-Wallis test, Friedman's test, in the non-parametric category. SOCR Analyses also include several hypothesis test models, such as Contingency tables, Friedman's test and Fisher's exact test. The code itself is open source (http://socr.googlecode.com/), hoping to contribute to the efforts of the statistical computing community. The code includes functionality for each specific analysis model and it has general utilities that can be applied in various statistical computing tasks. For example, concrete methods with API (Application Programming Interface) have been implemented in statistical summary, least square solutions of general linear models, rank calculations, etc. HTML interfaces, tutorials, source code, activities, and data are freely available via the web (www.SOCR.ucla.edu). Code examples for developers and demos for educators are provided on the SOCR Wiki website. In this article, the pedagogical utilization of the SOCR Analyses is discussed, as well as the underlying design framework. As the SOCR project is on-going and more functions and tools are being added to it, these resources are constantly improved. The reader is strongly encouraged to check the SOCR site for most updated information and newly added models. PMID:21546994

[Curative effect analysis of bile reinfusion combined with enteral nutrition support before surgery of hilar cholangiocarcinoma].

PubMed

Song, P; Mao, L; Bian, X J; Zhou, T; Fan, Y Y; Zhang, J; Xie, M; Qiu, Y D

2018-05-01

Objective: To investigate the clinical effect of bile reinfusion combined with enteral nutrition support before surgery for hilar cholangiocarcinoma. Methods: A retrospective analysis of patients with hilar cholangiocarcinoma who underwent surgical treatment at Nanjing Drum Tower Hospital Hepato-biliary-pancreatic Surgery Department from July 2010 to August 2017 was completed.A total of 52 cases were finally enrolled in our study.All the patients included, on the basis of whether they received preoperative drainage and bile reinfusion, were divided into non-drainage group( n =15) and drainage group( n =37). Differences of clinical indicators, including operation time, intraoperative bleeding and serum liver function index levels at day 1, 3, 7 postoperative, postoperative complications(liver failure, biliary fistula, pleural effusion, peritoneal effusion, abdominal cavity infection, death in hospital), tumor classification, R0 resection, postoperative hospitalization time between the 2 groups were analyzed. At the same time, in the drainage group, patients were divided into non-enteral nutrition subgroup( n =13) and enteral nutrition subgroup( n =24) according to whether they received enteral nutrition before operation. The normal distribution data of the group was statistically analyzed by independent sample t test, the non-normal distribution data of the group was statistically analyzed by rank-sum test. The count data was statistically analyzed by non-calibration and correction of the square test. Results: There was no statistically significant difference in general infomation such as age, gender, and serum liver function between non-drainage group and drainage group( P >0.05). There was no statistically significant difference in general information such as age, gender, and serum liver function between non-enteral nutrition group and enteral nutrition group( P >0.05). The rate of vascular resection and reconstruction(33.3%) and operating time(10.8(2.2)h) in drainage group were both higher than those in non-drainage group(6.7% and 8.3(3.0)h), the differences were both statistically significant(χ(2)=4.397, Z =1.595; both P <0.05). The level of AST at the 7th day after surgery in drainage group(32.8(17.3)U/L) was significantly lower than that in non-drainage group(55.0(64.7)U/L), the difference was statistically significant( Z =-2.212, P <0.05). The level of TBil at 1st day after surgery in drainage group(43.6(91.2)μmol/L) was lower than that in non-drainage group(91.2(188.4)μmol/L), the difference was statistically significant( Z =-2.150, P <0.05). The rate of pancreatoduodenectomy(25.0%) and average operating time(11.1(1.3)h) in the enteral nutrition group were both higher than those in the non-enteral nutrition group(0, 9.0(2.6)h). The differences were both statistically significant(χ(2)=3.879, Z =-2.693; P <0.05). The average level of AST at the 1st day after surgery in enteral nutrition group(396.4(268.3)U/L) was significantly lower than that in non-enteral nutrition group(642.5(341.1)U/L), the difference was statistically significant( Z =-2.483, P <0.05). The average level of TBil at the 1st, 3th day after surgery in enteral nutrition group(38.8(21.5)μmol/L and 30.0(25.6)μmol/L) were both lower than those in non-enteral nutrition group(60.9(75.2)μmol/L and 46.5(50.0)μmol/L), the differences were both statistically significant( Z =-2.416, -2.026; P <0.05). The level of CRP at 1st, 3th day after surgery((41.9±31.1)mg/L, (50.8±31.4)mg/L)in enteral nutrition subgroup was lower than that in non-enteral nutrition subgroup((64.4±33.6)mg/L, (74.1±35.3)mg/L), the differences were both statistically significant( t =1.456, 1.675; P <0.05). Conclusion: Based on the present study , there is no effective improvement on postoperative recovery using bile reinfusion combined with nutrition support before R0 resection of hilar cholangiocarcinoma.

Is typing speed proportional to the severity of pain in keyboard workers with work-related upper limb disorder

PubMed Central

Povlsen, Bo

2012-01-01

Objectives To investigate if typing speed is proportional to the severity of pain in keyboard workers with work-related upper limb disorder (WRULD). Design Standardized functional typing test with participants scoring pain before and after typing; calculation of typing speed. Participants Fifty-nine patients and six controls. Setting Tertiary hospital centre for hand and upper limb pain. Main outcome measures Pain (VAS 0–10) and calculation of typing speed as words per minute. Results Three subgroups of patients were found based on their typing speed: fast, slow and intermediate. Two-tailed student T-test with P level at 0.05 was used for evaluation. The typing speeds were significantly different between all three patient groups (P < 0.05). The typing speed was significantly faster in the fastest patient group than in the control group (P = 0.04) and the slow and middle groups (P = < 0.0001). The pain before typing was highest in the ‘slow’ group, in both hands but this difference was not statistically significant. Conclusion Typing speed is not proportional to the severity of pain in keyboard workers with WRULD. Patients with statistically significant slower or faster typing speeds do not have statistically different levels of pain. PMID:22299070

Virtual and stereoscopic anatomy: when virtual reality meets medical education.

PubMed

de Faria, Jose Weber Vieira; Teixeira, Manoel Jacobsen; de Moura Sousa Júnior, Leonardo; Otoch, Jose Pinhata; Figueiredo, Eberval Gadelha

2016-11-01

OBJECTIVE The authors sought to construct, implement, and evaluate an interactive and stereoscopic resource for teaching neuroanatomy, accessible from personal computers. METHODS Forty fresh brains (80 hemispheres) were dissected. Images of areas of interest were captured using a manual turntable and processed and stored in a 5337-image database. Pedagogic evaluation was performed in 84 graduate medical students, divided into 3 groups: 1 (conventional method), 2 (interactive nonstereoscopic), and 3 (interactive and stereoscopic). The method was evaluated through a written theory test and a lab practicum. RESULTS Groups 2 and 3 showed the highest mean scores in pedagogic evaluations and differed significantly from Group 1 (p < 0.05). Group 2 did not differ statistically from Group 3 (p > 0.05). Size effects, measured as differences in scores before and after lectures, indicate the effectiveness of the method. ANOVA results showed significant difference (p < 0.05) between groups, and the Tukey test showed statistical differences between Group 1 and the other 2 groups (p < 0.05). No statistical differences between Groups 2 and 3 were found in the practicum. However, there were significant differences when Groups 2 and 3 were compared with Group 1 (p < 0.05). CONCLUSIONS The authors conclude that this method promoted further improvement in knowledge for students and fostered significantly higher learning when compared with traditional teaching resources.

Effect of Oil Application, Age, Diet, and Pigmentation on the Tensile Strength and Breaking Point of Hair.

PubMed

Kavitha, S; Natarajan, Karthika; Thilagavathi, G; Srinivas, C R

2016-01-01

Hair strength depends on various factors such as nutrition, environmental factors, sunlight, oiling, aging, conditioner, etc. To compare the tensile strength and breaking point of the hair shaft between (1) vegetarian and nonvegetarian. (2) Those who regularly apply and those who do not apply oil. (3) Pigmented and nonpigmented hair, (4) childhood and elderly. Hair fibers were mounted in tensile strength testing machine Zwick/Roell Z010 and gradual force was administered. The elongation of hair fiber in mm and the maximum force required to break the hair strand were recorded for each fiber. Elasticity of the children's hair was more than the elasticity of adult ( P = 0.05) although tensile strength in children hair was not statistically significant (>0.05). Similarly, the tensile strength was more among those who regularly consumed nonvegetarian food but the difference was not statistically significant ( P > 0.05). There was no statistically significant difference in other groups ( P > 0.05). Elasticity in children hair is statistically more than elderly hair although there is no significant change in tensile strength.

Determinism and mass-media portrayals of genetics.

PubMed Central

Condit, C M; Ofulue, N; Sheedy, K M

1998-01-01

Scholars have expressed concern that the introduction of substantial coverage of "medical genetics" in the mass media during the past 2 decades represents an increase in biological determinism in public discourse. To test this contention, we analyzed the contents of a randomly selected, structured sample of American public newspapers (n=250) and magazines (n=722) published during 1919-95. Three coders, using three measures, all with intercoder reliability >85%, were employed. Results indicate that the introduction of the discourse of medical genetics is correlated with both a statistically significant decrease in the degree to which articles attribute human characteristics to genetic causes (P<.001) and a statistically significant increase in the differentiation of attributions to genetic and other causes among various conditions or outcomes (P<. 016). There has been no statistically significant change in the relative proportions of physical phenomena attributed to genetic causes, but there has been a statistically significant decrease in the number of articles assigning genetic causes to mental (P<.002) and behavioral (P<.000) characteristics. These results suggest that the current discourse of medical genetics is not accurately described as more biologically deterministic than its antecedents. PMID:9529342

Melody and pitch processing in five musical savants with congenital blindness.

PubMed

Pring, Linda; Woolf, Katherine; Tadic, Valerie

2008-01-01

We examined absolute-pitch (AP) and short-term musical memory abilities of five musical savants with congenital blindness, seven musicians, and seven non-musicians with good vision and normal intelligence in two experiments. In the first, short-term memory for musical phrases was tested and the savants and musicians performed statistically indistinguishably, both significantly outperforming the non-musicians and remembering more material from the C major scale sequences than random trials. In the second experiment, participants learnt associations between four pitches and four objects using a non-verbal paradigm. This experiment approximates to testing AP ability. Low statistical power meant the savants were not statistically better than the musicians, although only the savants scored statistically higher than the non-musicians. The results are evidence for a musical module, separate from general intelligence; they also support the anecdotal reporting of AP in musical savants, which is thought to be necessary for the development of musical-savant skill.

Consequences of common data analysis inaccuracies in CNS trauma injury basic research.

PubMed

Burke, Darlene A; Whittemore, Scott R; Magnuson, David S K

2013-05-15

The development of successful treatments for humans after traumatic brain or spinal cord injuries (TBI and SCI, respectively) requires animal research. This effort can be hampered when promising experimental results cannot be replicated because of incorrect data analysis procedures. To identify and hopefully avoid these errors in future studies, the articles in seven journals with the highest number of basic science central nervous system TBI and SCI animal research studies published in 2010 (N=125 articles) were reviewed for their data analysis procedures. After identifying the most common statistical errors, the implications of those findings were demonstrated by reanalyzing previously published data from our laboratories using the identified inappropriate statistical procedures, then comparing the two sets of results. Overall, 70% of the articles contained at least one type of inappropriate statistical procedure. The highest percentage involved incorrect post hoc t-tests (56.4%), followed by inappropriate parametric statistics (analysis of variance and t-test; 37.6%). Repeated Measures analysis was inappropriately missing in 52.0% of all articles and, among those with behavioral assessments, 58% were analyzed incorrectly. Reanalysis of our published data using the most common inappropriate statistical procedures resulted in a 14.1% average increase in significant effects compared to the original results. Specifically, an increase of 15.5% occurred with Independent t-tests and 11.1% after incorrect post hoc t-tests. Utilizing proper statistical procedures can allow more-definitive conclusions, facilitate replicability of research results, and enable more accurate translation of those results to the clinic.

Identifying irregularly shaped crime hot-spots using a multiobjective evolutionary algorithm

NASA Astrophysics Data System (ADS)

Wu, Xiaolan; Grubesic, Tony H.

2010-12-01

Spatial cluster detection techniques are widely used in criminology, geography, epidemiology, and other fields. In particular, spatial scan statistics are popular and efficient techniques for detecting areas of elevated crime or disease events. The majority of spatial scan approaches attempt to delineate geographic zones by evaluating the significance of clusters using likelihood ratio statistics tested with the Poisson distribution. While this can be effective, many scan statistics give preference to circular clusters, diminishing their ability to identify elongated and/or irregular shaped clusters. Although adjusting the shape of the scan window can mitigate some of these problems, both the significance of irregular clusters and their spatial structure must be accounted for in a meaningful way. This paper utilizes a multiobjective evolutionary algorithm to find clusters with maximum significance while quantitatively tracking their geographic structure. Crime data for the city of Cincinnati are utilized to demonstrate the advantages of the new approach and highlight its benefits versus more traditional scan statistics.

The frequency of dyscalculia among primary school children.

PubMed

Jovanović, Gordana; Jovanović, Zoran; Banković-Gajić, Jelena; Nikolić, Anđelka; Svetozarević, Srđana; Ignjatović-Ristić, Dragana

2013-06-01

Formal education, daily living activities and jobs require knowledge and application skills of counting and simple mathematical operations. Problems with mathematics start in primary school and persist till adulthood. This is known as dyscalculia and its prevalence in the school population ranges from 3 to 6.5%. The study included 1424 third-grade students (aged 9-10) of all primary schools in the City of Kragujevac, Serbia. Tests in mathematics were given in order to determine their mathematical achievement. 1078 students (538 boys and 540 girls) completed all five tests. The frequency of dyscalculia in the sample was 9.9%. The difference between boys and girls according to the total score on the test was statistically significant (p<0.005). The difference between students according to their school achievement (excellent, very good, good, sufficient and insufficient) was statistically significant for all tests (p<0.0005). The influence of place of residence/school was significant for all tests (p<0.0005). Independent prognostic variables associated with dyscalculia are marks in mathematics and Serbian language. Frequency of dyscalculia of 9.9% in the sample is higher than in the other similar studies. Further research should identify possible causes of such frequency of dyscalculia in order to improve students` mathematical abilities.

Effect of Metformin and Flutamide on Anthropometric Indices and Laboratory Tests in Obese/Overweight PCOS Women under Hypocaloric Diet.

PubMed

Amiri, Mania; Golsorkhtabaramiri, Masoumeh; Esmaeilzadeh, Sedigheh; Ghofrani, Faeze; Bijani, Ali; Ghorbani, Leila; Delavar, Moloud Agajani

2014-10-01

This study was designed to investigate the effect of metformin and flutamide alone or in combination with anthropometric indices and laboratory tests of obese/overweight PCOS women under hypocaloric diet. This single blind clinical trial was performed on 120 PCOS women. At the beginning, hypocaloric diet was recommended for the patients. After one month while they were on the diet, the patients were randomly divided in 4 groups; metformin (500 mg, 3/day), flutamide (250 mg, 2/day), combined, metformin (500 mg, 3/day) with flutamide (250 mg, 2/day) and finally placebo group. The patients were treated for 6 months. Anthropometric indices and laboratory tests (fasting and glucose-stimulated insulin levels, lipid profile and androgens) were measured. A one-way ANOVA (Post Hoc) and paired t-test were performed to analyze data. A p ≤ 0.05 was considered statistically significant. After treatment, reduction in weight, BMI, hip circumference was significantly greater in the metformin group in comparison to other groups (p<0.05). In addition, the fasting insulin was significantly greater in metformin group and flutamide group in comparison to metformin+flutamide and placebo groups after treatment (p<0.05). Within groups, insulin level showed significant changes (before and after treatment) in metformin+flutamide group and LDL reduction was significant in flutamide group before and after treatment. Post hoc tukey and two-tailed with p≤0.05 were used to define statistical significance. Using combination of metformin and flutamide improves anthropometric indices and laboratory tests in obese/overweight PCOS women under hypocaloric diet.

Biostatistics Series Module 2: Overview of Hypothesis Testing.

PubMed

Hazra, Avijit; Gogtay, Nithya

2016-01-01

Hypothesis testing (or statistical inference) is one of the major applications of biostatistics. Much of medical research begins with a research question that can be framed as a hypothesis. Inferential statistics begins with a null hypothesis that reflects the conservative position of no change or no difference in comparison to baseline or between groups. Usually, the researcher has reason to believe that there is some effect or some difference which is the alternative hypothesis. The researcher therefore proceeds to study samples and measure outcomes in the hope of generating evidence strong enough for the statistician to be able to reject the null hypothesis. The concept of the P value is almost universally used in hypothesis testing. It denotes the probability of obtaining by chance a result at least as extreme as that observed, even when the null hypothesis is true and no real difference exists. Usually, if P is < 0.05 the null hypothesis is rejected and sample results are deemed statistically significant. With the increasing availability of computers and access to specialized statistical software, the drudgery involved in statistical calculations is now a thing of the past, once the learning curve of the software has been traversed. The life sciences researcher is therefore free to devote oneself to optimally designing the study, carefully selecting the hypothesis tests to be applied, and taking care in conducting the study well. Unfortunately, selecting the right test seems difficult initially. Thinking of the research hypothesis as addressing one of five generic research questions helps in selection of the right hypothesis test. In addition, it is important to be clear about the nature of the variables (e.g., numerical vs. categorical; parametric vs. nonparametric) and the number of groups or data sets being compared (e.g., two or more than two) at a time. The same research question may be explored by more than one type of hypothesis test. While this may be of utility in highlighting different aspects of the problem, merely reapplying different tests to the same issue in the hope of finding a P < 0.05 is a wrong use of statistics. Finally, it is becoming the norm that an estimate of the size of any effect, expressed with its 95% confidence interval, is required for meaningful interpretation of results. A large study is likely to have a small (and therefore "statistically significant") P value, but a "real" estimate of the effect would be provided by the 95% confidence interval. If the intervals overlap between two interventions, then the difference between them is not so clear-cut even if P < 0.05. The two approaches are now considered complementary to one another.

Associations between neural injury markers of intrauterine growth-restricted infants and neurodevelopment at 2 years of age.

PubMed

Mazarico, E; Llurba, E; Cabero, L; Sánchez, O; Valls, A; Martín-Ancel, A; Cardenas, D; Gómez Roig, M D

2018-04-18

The aim of this study was to evaluate the relationships between brain injury biomarkers in intrauterine growth-restricted (IUGR) infants (S100B and neuron-specific enolase (NSE)) and neurodevelopment at 2 years of age. This prospective case-control study was a cooperative effort among Spanish Maternal and Child Health Network (Retic SAMID) hospitals. At inclusion, biometry for estimated fetal weight and feto-placental Doppler variables were measured for each infant. Maternal venous blood and fetal umbilical arterial blood samples were collected at the time of delivery and neural injury markers S100B and NSE concentrations were measured. Neurodevelopment was evaluated at 2 years of age using the Bayley Scales of Infant and Toddler Development, third edition (Bayley-III). Fifty six pregnancies were included. Thirty-one infants were classified as IUGR and 25 as non-IUGR. Neurodevelopmental evaluation at 2 years of age indicated that there were no between-group differences for any of the tests. For all patients in both groups, we found statistically significant inverse relationships between the concentrations of NSE in the cord blood and the results of the cognitive test (r = -271, p = .042), fine motor subtest (r = -280, p = .036), and social-emotional test (r = -349, p = .015). We also found statistically significant differences between the concentrations of S100B in the cord blood and the results of the cognitive test (r = -306, p = .022) and expressive communication subtest (r = -304, p = .023). For the IUGR group, we found a significant inverse relationship between the concentrations of S100B in the maternal serum and the results of adaptive behavior test (p < .05). In the non-IUGR group, we found statistically significant inverse relationships between the concentration of NSE in the cord blood and the results of the fine motor subtest (r = -446, p = .025) and social-emotional test (r = -489, p = .021). The difference between the concentration of S100B in the cord blood and the language composite score was also statistically significant (p = .038). At 2 years of age, the concentrations of NSE and S100B were higher in the non-IUGR and IUGR groups with the worst scores for some areas of neurodevelopmental evaluation. The value of these biomarkers for prognostic neurodevelopmental use requires further investigation for both non-IUGR and IUGR infants.

Statistical Analysis of the Polarimetric Cloud Analysis and Seeding Test (POLCAST) Field Projects

NASA Astrophysics Data System (ADS)

Ekness, Jamie Lynn

The North Dakota farming industry brings in more than $4.1 billion annually in cash receipts. Unfortunately, agriculture sales vary significantly from year to year, which is due in large part to weather events such as hail storms and droughts. One method to mitigate drought is to use hygroscopic seeding to increase the precipitation efficiency of clouds. The North Dakota Atmospheric Research Board (NDARB) sponsored the Polarimetric Cloud Analysis and Seeding Test (POLCAST) research project to determine the effectiveness of hygroscopic seeding in North Dakota. The POLCAST field projects obtained airborne and radar observations, while conducting randomized cloud seeding. The Thunderstorm Identification Tracking and Nowcasting (TITAN) program is used to analyze radar data (33 usable cases) in determining differences in the duration of the storm, rain rate and total rain amount between seeded and non-seeded clouds. The single ratio of seeded to non-seeded cases is 1.56 (0.28 mm/0.18 mm) or 56% increase for the average hourly rainfall during the first 60 minutes after target selection. A seeding effect is indicated with the lifetime of the storms increasing by 41 % between seeded and non-seeded clouds for the first 60 minutes past seeding decision. A double ratio statistic, a comparison of radar derived rain amount of the last 40 minutes of a case (seed/non-seed), compared to the first 20 minutes (seed/non-seed), is used to account for the natural variability of the cloud system and gives a double ratio of 1.85. The Mann-Whitney test on the double ratio of seeded to non-seeded cases (33 cases) gives a significance (p-value) of 0.063. Bootstrapping analysis of the POLCAST set indicates that 50 cases would provide statistically significant results based on the Mann-Whitney test of the double ratio. All the statistical analysis conducted on the POLCAST data set show that hygroscopic seeding in North Dakota does increase precipitation. While an additional POLCAST field project would be necessary to obtain standardly accepted statistically significant results (p < 0.5) for the double ratio of precipitation amount, the obtained p-value of 0.063 is close and considering the positive result from other hygroscopic seeding experiments, the North Dakota Cloud Modification Project should consider implementation of hygroscopic seeding.

Randomized trial of parent training to prevent adolescent problem behaviors during the high school transition.

PubMed

Mason, W Alex; Fleming, Charles B; Gross, Thomas J; Thompson, Ronald W; Parra, Gilbert R; Haggerty, Kevin P; Snyder, James J

2016-12-01

This randomized controlled trial tested a widely used general parent training program, Common Sense Parenting (CSP), with low-income 8th graders and their families to support a positive transition to high school. The program was tested in its original 6-session format and in a modified format (CSP-Plus), which added 2 sessions that included adolescents. Over 2 annual cohorts, 321 families were enrolled and randomly assigned to either the CSP, CSP-Plus, or minimal-contact control condition. Pretest, posttest, 1-year follow-up, and 2-year follow-up survey data on parenting as well as youth school bonding, social skills, and problem behaviors were collected from parents and youth (94% retention). Extending prior examinations of posttest outcomes, intent-to-treat regression analyses tested for intervention effects at the 2 follow-up assessments, and growth curve analyses examined experimental condition differences in yearly change across time. Separate exploratory tests of moderation by youth gender, youth conduct problems, and family economic hardship also were conducted. Out of 52 regression models predicting 1- and 2-year follow-up outcomes, only 2 out of 104 possible intervention effects were statistically significant. No statistically significant intervention effects were found in the growth curve analyses. Tests of moderation also showed few statistically significant effects. Because CSP already is in widespread use, findings have direct implications for practice. Specifically, findings suggest that the program may not be efficacious with parents of adolescents in a selective prevention context and may reveal the limits of brief, general parent training for achieving outcomes with parents of adolescents. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Awareness and Attitude of the General Public Toward HIV/AIDS in Coastal Karnataka

PubMed Central

Unnikrishnan, B; Mithra, Prasanna P; T, Rekha; B, Reshmi

2010-01-01

Objective: To assess the awareness and attitude of the general public toward people living with HIV/AIDS (PLWHA) in Mangalore, a city in Coastal Karnataka. Design: Community-based cross-sectional study. Materials and Methods: The study population included 630 individuals aged 18 years and above. The information was collected using a semi structured pre-tested questionnaire. The questionnaire consisted of 24 questions regarding awareness of the modes of transmission of HIV/AIDS (nine questions) and questions to assess the attitude toward People Living With HIV/AIDS (PLWHA) (15 questions). Statistical package SPSS version 11.5 was used, Chi-square test was conducted and P < 0.05 was considered as statistically significant. Results: About one-third of the study population thought that one could get infected by merely touching an HIV positive individual. Approximately 45% stated that they would dismiss their maid on finding out her HIV positive status. About 54% were willing to undergo the HIV test. The respondents with less than secondary school education had a discriminatory attitude toward HIV positive people, with regard to them deserving to suffer, dismissing a HIV positive maid, hesitating to sit next to a HIV positive person in the bus, divorcing the infected spouse, and willingness to get tested for HIV, which was found to be statistically significant. Conclusion: Stigma among the general public was mostly due to fear of contracting the illness. Stigma does exist to significant degrees among the educated people, which was suggested by about 45% of the participants being willing to undergo the HIV test. There is a need for greater attempts toward making information regarding HIV/AIDS available to every individual of the society. PMID:20606940

Satisfaction with cancer care among underserved racial-ethnic minorities and lower-income patients receiving patient navigation.

PubMed

Jean-Pierre, Pascal; Cheng, Ying; Wells, Kristen J; Freund, Karen M; Snyder, Frederick R; Fiscella, Kevin; Holden, Alan E; Paskett, Electra D; Dudley, Donald J; Simon, Melissa A; Valverde, Patricia A

2016-04-01

Patient navigation is a barrier-focused program of care coordination designed to achieve timely and high-quality cancer-related care for medically underserved racial-ethnic minorities and the poor. However, to the authors' knowledge, few studies to date have examined the relationship between satisfaction with navigators and cancer-related care. The authors included data from 1345 patients with abnormal cancer screening tests or a definitive cancer diagnosis who participated in the Patient Navigation Research Program to test the efficacy of patient navigation. Participants completed demographic questionnaires and measures of patient satisfaction with cancer-related care (PSCC) and patient satisfaction with interpersonal relationship with navigator (PSN-I). The authors obtained descriptive statistics to characterize the sample and conducted regression analyses to assess the degree of association between PSN-I and PSCC, controlling for demographic and clinical factors. Analyses of variance were conducted to examine group differences controlling for statistically significant covariates. Statistically significant relationships were found between the PSCC and PSN-I for patients with abnormal cancer screening tests (1040 patients; correlation coefficient (r), 0.4 [P<.001]) and those with a definitive cancer diagnosis (305 patients; correlation coefficient, 0.4 [P<.001]). The regression analysis indicated that having an abnormal colorectal cancer screening test in the abnormal screening test group and increased age and minority race-ethnicity status in the cancer diagnosis group were associated with a higher satisfaction with cancer care (P<.01). Satisfaction with navigators appears to be significantly associated with satisfaction with cancer-related care. Information regarding the patient-navigator relationship should be integrated into patient navigation programs to maximize the likelihood of reducing caner disparities and mortality for medically underserved racial-ethnic minorities and the poor. © 2016 American Cancer Society.

Do Effect-Size Measures Measure up?: A Brief Assessment

ERIC Educational Resources Information Center

Onwuegbuzie, Anthony J.; Levin, Joel R.; Leech, Nancy L.

2003-01-01

Because of criticisms leveled at statistical hypothesis testing, some researchers have argued that measures of effect size should replace the significance-testing practice. We contend that although effect-size measures have logical appeal, they are also associated with a number of limitations that may result in problematic interpretations of them…

Aronia melanocarpa Treatment and Antioxidant Status in Selected Tissues in Wistar Rats

PubMed Central

Krośniak, Mirosław; Sanocka, Ilona; Bartoń, Henryk; Hebda, Tomasz; Francik, Sławomir

2014-01-01

Aronia juice is considered to be a source of compounds with high antioxidative potential. We conducted a study on the impact of compounds in the Aronia juice on oxidative stress in plasma and brain tissues. The influence of Aronia juice on oxidative stress parameters was tested with the use of a model with a high content of fructose and nonsaturated fats. Therefore, the activity of enzymatic (catalase, CAT, and paraoxonase, PON) and nonenzymatic (thiol groups, SH, and protein carbonyl groups, PCG) oxidative stress markers, which indicate changes in the carbohydrate and protein profiles, was marked in brain tissue homogenates. Adding Aronia caused statistically significant increase in the CAT activity in plasma in all tested diets, while the PON activity showed a statistically significant increase only in case of high fat diet. In animals fed with Aronia juice supplemented with carbohydrates or fat, statistically significant increase in the PON activity and the decrease in the CAT activity in brain tissue were observed. In case of the high fat diet, an increase in the number of SH groups and a decrease in the number of PCG groups in brain tissue were observed. PMID:25057488