This Monte-Carlo study compared modified Newton (NW), expectation-maximization algorithm (EM), and minimum Cramer-von Mises distance (MD), used to estimate parameters of univariate mixtures of two components. Data sets were fixed at size 160 and manipulated by mean separation, variance ratio, component proportion, and non-normality. Results…

This study was designed to look for patterns of parental behavior by assessing styles of child rearing in a novel way--through responses on an interactive computer program simulating an average day in the life of a mother and a preschooler. Presented to each subject (39 mothers of preschoolers and a control group of non-mothers) were 30 common…

Complex decision-making environments often demand that a range of alternative strategies be identified and compared for their shared value in achieving desired ends. Simple parametric statistical procedures such as analysis of variance and discriminant function analysis can be used in such situations to compare (using selected criteria) the value…

This paper investigates three methods for comparing medians rather than means in studying two independent treatment groups. The method that gave the best results is based on a normal approximation of the distribution of the sample median where the variance is estimated using results reported by Maritz and Jarrett. (Author/JAZ)

This study compared the performance of the LOGIST and BILOG computer programs on item response theory (IRT) based scaling and equating for the Test of English as a Foreign Language (TOEFL) using real and simulated data and two calibration structures. Applications of IRT for the TOEFL program are based on the three-parameter logistic (3PL) model.…

A logistic regression model for characterizing differential item functioning (DIF) between two groups is presented. A distinction is drawn between uniform and nonuniform DIF in terms of model parameters. A statistic for testing the hypotheses of no DIF is developed, and simulation studies compare it with the Mantel-Haenszel procedure. (Author/TJH)

This study showed that the Elementary Perceiver and Memorizer (EPAM) can explain letter recognition phenomena earlier simulated by the connectionist Interactive Activation Model of word perception. EAPM, a model of learning and recognition in the form of a computer program, has previously explained many aspects of learning and perception. (TJH)

A modification of a test of the equality of nonindependent alpha reliability coefficients is proposed. It avoids the limitation that the product of the number of test parts times the number of subjects be quite large. Monte Carlo studies indicate that this test can be used in comparing interrater reliabilities. (SLD)

This study was designed to investigate the impact of using computer-simulated (virtual ) manipulatives and hands-on (concrete) manipulatives on elementary students' learning skills and concepts in equivalent fractions. The researcher's primary interest was whether or not students who used virtual manipulatives would out-perform students who used…

The Random Normal Scores Test (RNST) has been suggested as a powerful alternative to the use of the parametric analysis of variance (ANOVA) test when the underlying population is non-normally distributed. The major support for this suggestion rests on asymptotic theory. An empirical analysis of the RNST performed under the F and Chi-square…

Describes the emphasis of decision support systems as being on the decision making process itself, rather than the flow of information; reviews the uses of microcomputers in libraries in recent years; and compares five decision modeling software packages. An appendix lists the name, manufacturer's address, price, and hardware requirements of each…

Compares results of giving undergraduate students actual instructor feedback, computer-simulated instructor feedback, or no feedback. There were advantages to giving actual instructor-supplied feedback for exam performance, in-class responsiveness, and attitudes toward the instructor and other students. (JMV)

Ignorance of the characteristics of a mixed population may lead to bias in a summary measure of a phenomenon. A test based on sample kurtosis is demonstrated by a simulation study to be more powerful than six other known tests in detecting a class of mixed normal distributions. (SLD)

Two issues in analysis of interactions in complex linear models are considered. One is the omnibus test for interaction, and the other concerns follow-up tests when the omnibus test is significant. Reconsidered omnibus and follow-up tests are illustrated on an educational data set analyzed using the Statistical Analysis System. (SLD)

To examine cultural differences in planning processes, two instruments, one of which was a computer simulation, were used with 38 Brazilian and 38 German university students. Results are discussed from a functional perspective that interprets cognitive processes within their ecocultural context. (SLD)