Power divergence statistics under quasi independence model for square contingency tables

In incomplete contingency tables, some cells may contain structural zeros. The quasi-independence model, which is a generalization of the independence model, is most commonly model used to analyze incomplete contingency tables. Goodness of fit tests of the quasi-independence model are usually based on Pearson chi square test statistic and likelihood ratio test statistic. In power divergence statistics family, the selection of power divergence parameter is of interest in multivariate discrete data. In this study, a simulation study is conducted to evaluate the performance of the power divergence statistics under quasi independence model for particular power divergence parameters in terms of power values

Specification of Variance-Covariance Structure in Bivariate Mixed Model for Unequally Time-Spaced Longitudinal Data

In medical studies, the longitudinal data sets obtained from more than one response variables and covariates are mostly analyzed to investigate the change in repeated measurements of each subject at different time points. In this study, the usability of multivariate models in the analysis of these kind of data sets is investigated, because it provides the joint analysis of multiple response variables over time and enables researchers to examine both the correlations of response variables and autocorrelation between measurements from each response variable over time. It has been shown that different parameter estimation methods affect the results in the analysis of multivariate unbalanced longitudinal data. We investigated that autocorrelation structure over time between measurements from same response variable should be truly specified. We also illustrated and compared the simpler, more standard models for fixed effects with multivariate models provided by SAS on a real-life data set in the joint analysis of two response variables. Results show that misspecification of autocorrelation structures has a negative impact on the parameter estimates and parameter estimation method should become of interest

Students’ Opinions About Science and Technology in Turkey and the United States: A Cross-Cultural Study

The aim of this study is to determine the thoughts of Turkish and American middle school students on science and technology. One intact school was assigned randomly for this study from both countries. The sampling of the study contains 479 students (363 Turkish students, 116 American students) from two countries aged between 11 and 13. The data for the study were obtained by using ROSE Survey. The results of the study revealed similarities and dissimilarities on science and technology between the students of the two countries. The findings of the study are thought to improve the education of universal science and technology and to contribute to the researchers doing research on comparative education and cultural diversity and to the literature of international science education

STUDENTS’ OPINIONS ABOUT SCIENCE AND TECHNOLOGY IN TURKEY AND THE UNITED STATES: A CROSS-CULTURAL STUDY

The aim of this study is to determine the thoughts of Turkish and American middle school students on science and technology. One intact school was assigned randomly for this study from both countries. The sampling of the study contains 479 students (363 Turkish students, 116 American students) from two countries aged between 11 and 13. The data for the study were obtained by using ROSE Survey. The results of the study revealed similarities and dissimilarities on science and technology between the students of the two countries. The findings of the study are thought to improve the education of universal science and technology and to contribute to the researchers doing research on comparative education and cultural diversity and to the literature of international science education.Keywords: curriculum and instruction, science education, middle school

Anderson localization in optical lattices with speckle disorder

We study the localization properties of non-interacting waves propagating in a speckle-like potential superposed on a one-dimensional lattice. Using a decimation/renormalization procedure, we estimate the localization length for a tight-binding Hamiltonian where site-energies are square-sinc-correlated random variables. By decreasing the width of the correlation function, the disorder patterns approaches a $\delta$-correlated disorder, and the localization length becomes almost energy-independent in the strong disorder limit. We show that this regime can be reached for a size of the speckle grains of the order of (lower than) four lattice steps.Comment: 4 pages, 1 figur

Median Distance Model for Likert-Type Items in Contingency Table Analysis

Likert-type items (questions) are a widely used scale in questionnaire design. The “neutral” or “undecided” option may lead to misinterpretation and confusion about the results. This paper proposes two novel log-linear models to measure how much accumulation of the neutral option over the contingency tables at any question levels. These models also test the odds that a respondent’s level how far from the median. These models will help the researchers how to incorporate the neutral option in conceptual frameworks

Comparisons Of Sum Of Squares Methods In Anova Models

The total sum of squares in ANOVA models is decomposed and the significances of the main term and interaction terms are tested. The four different methods called as Type I, II, III, and IV are used for calculating the sum of squares of the main effects and interactions. The model and data structures are crucial in the selection of the most appropriate method for applications. However, Type III method is adapted as the default sum of square method in most of the standard statistical software packages regardless of model and data structures. If the appropriate method is not selected, it directly affects the value of the F statistic and it may cause statistically invalid inferences. In this paper, the use of the sum of squares methods for various cases are indicated and the differences between the methods are discussed on two examples defined by a two-way ANOVA design.WoSTr-Dizi

Students’ Opinions About Science and Technology in Turkey and the United States: A Cross-Cultural Study

The aim of this study is to determine the thoughts of Turkish and American middle school students on science and technology. One intact school was assigned randomly for this study from both countries. The sampling of the study contains 479 students (363 Turkish students, 116 American students) from two countries aged between 11 and 13. The data for the study were obtained by using ROSE Survey. The results of the study revealed similarities and dissimilarities on science and technology between the students of the two countries. The findings of the study are thought to improve the education of universal science and technology and to contribute to the researchers doing research on comparative education and cultural diversity and to the literature of international science education

Autocorrelation Corrected Standard Error For Two Sample T-Test Under Serial Dependence

The classical two-sample t-test assumes that observations are independent. A violation of this assumption could lead to inaccurate results and incorrectly analyzing data leads to erroneous statistical inferences. However, in real life applications, data are often recorded over time and serial correlation is unavoidable. In this study, two new auto-correlation corrected standard errors are proposed for independent and correlated samples. These standard errors are replaced by the classical standard error in the presence of serially correlated samples in two samples t-test. Results based upon the simulation show that the proposed standard errors gives higher empirical power than other approaches.WoSScopu

Post-Hoc Comparison Tests for Odds Ratios

The null hypothesis of homogeneity of odds ratio across the strata is testedby several tests. When the null hypothesis is rejected, means at least one ofthe odds ratios signicantly diers from others. Post hoc tests are used afterthe null hypothesis of equality of groups is rejected. Those tests aim to revealthe true dierences between groups. In this paper, we propose post-hoc pro-cedures that control familywise type-I error. These procedures provide thehomogeneous subsets that appear in the same homogeneous subset that arenot signicantly dierent. The suggested procedures are applied to severalCOVID-19 data sets