Each of the four classic multivariate analysis of variance (MANOVA) tests of statistical significance may lead a researcher to different decisions as to whether a null hypothesis should be rejected: (1) Wilks' lambda; (2) Lawley-Hotelling trace criterion; (3) Roy's greatest characteristic root criterion; and (4) Pillai's trace criterion. These…

Attempts to distill a growing technical literature on repeated-measures analysis of variance into a few simple principles for selecting an analytic technique. Argues that researchers ought not opt for a general analysis strategy when current computer technology makes it possible to select the optimal analysis technique for a given data set. (RH)

Determination of statistical power for analysis of variance procedures requires five elements: (1) significance level; (2) effect size; (3) number of means; (4) error variance; and (5) sample size. Significance levels are traditionally chosen to be 0.5, .01, or .001. Effect size is not discussed in this paper. The number of means is determined by…

This tutorial summarizes some of the widely known limitations of tests of statistical significance and then focuses on extracting measures of variation accounted for as a supplement to significance testing. Two measures of variation accounted for, eta squared and omega squared, are discussed. Computational formulas, computational examples, and…

This paper focuses on two methods of performing multiple comparisons (post hoc or unplanned versus a priori or planned) for determining exactly where statistically significant results arise when there are more than "k equals two" groups. Textbook views and recommendations regarding the use of these two types of multiple comparisons are…

A dichotomous dependent variable is used to determine a combination of variables that will predict group membership. Dichotomous variables are frequently encountered in multiple regression analysis. However, several textbooks question the appropriateness of using multiple regression analysis when analyzing dichotomous dependent variables. The…

Statistical measures of practical significance report the extent to which variation in the dependent variable can be explained by the independent variable. Reports of special education research sometimes discuss practicality using the estimate of statistical significance. Practical significance, however, may vary greatly among samples even though…

This study focused on two questions: (1) whether the types of study-aid test, or the levels of test anxiety would affect the level of performance on the test under non-anxious conditions; and (2) whether there would be any interaction effect between the types of study-aid test and the levels of anxiety under non-anxious conditions. Twelve female…

Although technological innovations have been widely adopted in elementary schools, efforts to implement these have generally not been successful. Past research on innovation has largely ignored the social context in which implementation occurs. This research examines how the implementation of the microcomputer is affected by the traditional social…

Political communication researchers recently have emphasized conditional relationships as crucial to specifying and understanding the effects of the mass media. In many cases, however, researchers will not predict which variables will modify the form or existence of media effects. They therefore will not include measures of the conditional…

Hypothetical data sets are used to demonstrate how canonical correlation methods subsume other commonly utilized parametric methods. Analysis of variance, analysis of covariance, multiple analysis of variance, and multiple analysis of covariance are heavily used by educational researchers. It is concluded that researchers would do well to consider…

The study reported in this paper examined whether a disproportionate number of boys and girls in a given grade level at various schools might have an inequitable effect on the mean achievement test scores of those schools. The student population of the Palm Beach County Schools, Florida, reflecting a cross-section of socio-economic backgrounds,…

This 3-year study, part of the Effective Schools Project of the Seattle School District and the University of Washington, was undertaken to investigate the relationship between teachers' perceptions of the principal as instructional leader and average gain scores of students in 67 elementary schools in Seattle. Scores were disaggregated by student…

This paper reports the results of a Monte Carlo investigation of Type I errors in the single group repeated measures design where multiple measures are collected from each observational unit at each measurement occasion. The Type I error of three multivariate tests were examined. These were the doubly multivariate F test, the multivariate mixed…

This 2-year study, which took a multidisciplinary approach to the problem of discovering principles for designing effective multimedia instruction, focused on the effects on instructional effectiveness of the discourse structure of instructional materials and the coordination of multiple instructional media. The task domain was a logic box said to…