It is common to assume during statistical analysis of a multiscale assessment that the assessment has simple structure or that it is composed of several unidimensional subtests. Under this assumption, both the unidimensional and multidimensional approaches can be used to estimate item parameters. This paper theoretically demonstrates that these…

Report describes and makes a preliminary assessment of a data simulation computer program at the University of Michigan. (MF)

The negative bias of biserial correlations in the presence of guessing is demonstrated by Monte Carlo studies, and another estimator is described that is free of such bias. The usual biserial-correlation assumptions and assumptions about guessing are discussed. Brogden's coefficient of selective efficiency and the triserial correlation are…

A method for multidimensional scaling that is highly resistant to the effects of outliers is described. Some Monte Carlo simulations illustrate the efficacy of the procedure, which performs well with or without outliers. (SLD)

Through simulation, the power of the U3 statistic was compared with the power of one of the simplest person-fit statistics, the sum of the number of Guttman errors. In most cases, a weighted version of the latter statistic performed as well as the U3 statistic. (SLD)

Multidimensional unfolding methods suffer from the degeneracy problem in almost all circumstances. Most degeneracies are easily recognized: the solutions are perfect but trivial, characterized by approximately equal distances between points from different sets. A definition of an absolutely degenerate solution is proposed, which makes clear that…

It is well known that the two-sample Student t test fails to maintain its significance level when the variances of treatment groups are unequal, and, at the same time, sample sizes are unequal. However, introductory textbooks in psychology and education often maintain that the test is robust to variance heterogeneity when sample sizes are equal.…

This research examines empathic dispositions of 178 pre-service teachers. We analyzed open ended responses to animated narrative vignette simulations (ANVs), which served as stimulated experimental situations depicting students in victim and perpetrator scenarios. Empathy was examined by addressing the following questions: (1) Do participants'…

The production and operations management class offered at California State University, Fresno underwent a transformation from being a four-unit, face-to-face course to a hybrid course. This hybrid course, which is required for all students in the Craig School of Business, includes two units of face-to-face instruction each week, with some coverage…

The work of R. MacCallum et al. (1992) was extended by examining chance modifications through a Monte Carlo simulation. The stability of post hoc model modifications was examined under varying sample size, model complexity, and severity of misspecification using 2- and 4-factor oblique confirmatory factor analysis (CFA) models with four and eight…

Sequential probability ratio testing (PRT), which usually is applied in situations requiring a decision between two simple hypotheses or a single decision point, is extended to include situations involving k decision points and [(k + 1)-choose-2] sets of simultaneous, simple hypotheses, where k>1. The multiple-decision point or…

Multiple-hypothesis testing in the context of a correlation matrix is used to compare the statistical power of the original Bonferroni with six modified Bonferroni procedures that control the overall Type I error rate. Three definitions of statistical power are considered: (1) the ability to detect at least one true relationship; (2) the ability…

Three computer simulations were conducted to show that very high aggregate predictive validity coefficients can occur when the across-case variability in absolute score stability occurring in both the predictor and criterion matrices is quite small. In light of the increase in internal consistency reliability achieved by the method of aggregation…

The index term input to three information retrieval systems has been analyzed in detail in order to form the input to a completely computerized simulation of an information retrieval system. The paper reports that, with certain reservations, index terms conform in general with the Bradford distribution. (Author)

This study examines how closely the kernel equating (KE) method (von Davier, Holland, & Thayer, 2004a) approximates the results of other observed-score equating methods--equipercentile and linear equatings. The study used pseudotests constructed of item responses from a real test to simulate three equating designs: an equivalent groups (EG)…