A review of the literature indicates that the two best procedures for testing variances are one that was proposed by O'Brien (1981) and another that was proposed by Brown and Forsythe (1974). An examination of these procedures for a variety of populations confirms their robustness and indicates how optimal power can usually be obtained. (SLD)

The effect of reducing the number of score groups in the matching criterion of the Mantel-Haenszel procedure when screening for differential item functioning was investigated with a simulated data set. Results suggest that more than modest reductions cannot be recommended when ability distributions of reference and focal groups differ. (SLD)

The statistical analysis of processing tree models is advanced by showing how the parameters of estimation and hypothesis testing, based on the likelihood functions, can be accomplished by adapting the expectation-maximization (EM) algorithm. The adaptation makes it easy to program a personal computer to accomplish the stages of statistical…

Given a Masters partial credit item with n known step difficulties, conditions are stated for the existence of a set of (locally) independent Rasch binary items such that their raw score and the partial credit raw score have identical probability density functions. (Author/SLD)

A statistical power algorithm based on the Fisher Z method is developed for cutoff-based random clinical trials and the single cutoff-point (regression-discontinuity) design that has no randomization. This article quantifies power and sample size estimates for various levels of power and cutoff-based assignment. (Author/SLD)

Not infrequently, investigators assume that reliability for groups is greater than reliability for persons, or that the error variance for groups is less than that for persons. Using generalizability theory, it is shown that this "conventional wisdom" is not necessarily true. Examples are provided from the course-evaluation and the…

The nature of the criterion (dependent) variable may play a useful role in structuring a list of classification/prediction problems. Such criteria are continuous in nature, binary dichotomous, or multichotomous. In this paper, discussion is limited to the continuous normally distributed criterion scenarios. For both cases, it is assumed that the…

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…

Monte Carlo studies explored the sampling characteristics of Cohen's d and three approximations to Cohen's d when used as average effect size measures in meta-analysis. Reviews of 10, 100, and 500 studies (M) were simulated, with degrees of freedom (df) varied in seven steps from 8 to 58. In a two independent groups design, samples were obtained…

This study used multiple regression analyses to identify the socioeconomic, demographic and attitudinal correlates of neighborhood differences in the rate of child abuse and neglect. Comparison of actual vs. predicted rates defined high- and low-risk neighborhoods. These "risk scores" then become variables for inclusion in additional…

Statistical analysis of election results from four California counties over a twenty-year period (1956-1977) shows that the defeat of an incumbent school board member in one election increases the probability of incumbent defeats in the next three elections in the same district, while decreasing the probability of incumbent defeats in that…

The Goodman technique of log linear analysis is ideal for family research, because it is designed for categorical (non-quantitative) variables. Variables are dichotomized (for example, married/divorced, childless/with children) or otherwise categorized (for example, level of permissiveness, life cycle stage). Contingency tables are then…

The goal of this paper was to develop a theory of organization/environment interaction by examining the impact of perceived environmental uncertainty on organizational processes and on organizational goal attainment. It examines theories from the organizational environment literature and derives corollaries that are empirically tested using a data…

THIS DOCUMENT IS SECTION 1 OF A 3-PART REPORT BY THE EDUCATIONAL TESTING SERVICE. THIS SECTION DESCRIBES, IN EXTENSIVE STATISTICAL TERMS, A SAMPLE OF 445 HEAD START CHILDREN IN TERMS OF THEIR SCORES ON (1) THE STANFORD-BINET L-M, (2) THE CALDWELL PRESCHOOL INVENTORY, AND (3) THE PROJECT HEAD START BEHAVIOR INVENTORY. THE SAMPLING PROCEDURES USED…

Increasing interest over the last twenty years in quality Greek and Latin translations seems to be primarily a reflection of the "paperback revolution." Figures and trend reports from various publishers illustrate the burgeoning numbers of classical works in translation. This new availability has enabled students of literature, history, political…