The purpose of this article is to develop a statistical model that best explains variability in the number of school days suspended. Number of school days suspended is a count variable that may be zero-inflated and overdispersed relative to a Poisson model. Four models were examined: Poisson, negative binomial, Poisson hurdle, and negative…

A multilevel logistic model for estimating a nonlinear trajectory in a multiple-baseline design is introduced. The model is applied to data from a real multiple-baseline design study to demonstrate interpretation of relevant parameters. A simple change-in-levels (?"Levels") model and a model involving a quadratic function…

Educational researchers commonly use the rule of thumb of "design effect smaller than 2" as the justification of not accounting for the multilevel or clustered structure in their data. The rule, however, has not yet been systematically studied in previous research. In the present study, we generated data from three different models…

Users assume statistical software packages produce accurate results. In this article, the authors systematically examined Statistical Package for the Social Sciences (SPSS) and Statistical Analysis System (SAS) for 3 analysis of variance (ANOVA) designs, mixed-effects ANOVA, fixed-effects analysis of covariance (ANCOVA), and nested ANOVA. For each…

There is general agreement that meta-analysis is an important tool for synthesizing study results in quantitative educational research. Yet, a shared feature of many meta-analyses is a failure to report sufficient information for readers to fully judge the reported findings, such as the populations to which generalizations are to be made,…

Errors of misclassification and their effects on categorical data analysis are discussed. The chi-square test for equality of two proportions is examined in the context of errorful categorical data. The effects of such errors are illustrated. A correction procedure is developed and discussed. (Author/MH)

A study designed to compare the academic achievement of pupils in graded and non-graded schools using an Index of Non-gradedness to determine the validity of the term non-graded" as applied to some schools. (Author/RY)

To assess whether different response patterns were associated with differences in the naming and placement of response categories, 1000 undergraduate students in educational administration completed a 10-item personal-values questionnaire. (Author)

Using data from the National Study of Postsecondary Faculty and the Early Childhood Longitudinal Study--Kindergarten Class of 1998-99, the author provides guidelines for incorporating weights and design effects in single-level analysis using Windows-based SPSS and AM software. Examples of analyses that do and do not employ weights and design…

Considered the statistical comparison of groups under the condition of equal sample sizes. (Author)

A Monte Carlo technique was employed in order to compare the relative power and robustness of the Bartlett, Cochran, Hartley, and Levene tests for homogeniety of variance. (Editor)

The importance of the method given in the body of this article is that it presents Tukey's test in a greatly simplified form for the applied researcher. (Author)

Quite often in data reduction, it is more meaningful and economical to select a subset of variables instead of reducing the dimensionality of the variable space with principal components analysis. The authors present a neglected method for variable selection called the BI-method (R. P. Bhargava & T. Ishizuka, 1981). It is a direct, simple method…

Illustrates how expected mean squares needed in the analysis of variance can be arrived at via the use of only one rule: the expected mean square E(MS) for any source of variation for any ANOVA model is specified effect plus the specified effect in combination with any random effect. (Editor/RK)