This article compares two methods for analyzing small sets of repeated measures data under normal and non-normal heteroscedastic conditions: a mixed model approach with the Kenward-Roger correction and a multivariate extension of the modified Brown-Forsythe (BF) test. These procedures differ in their assumptions about the covariance structure of…

A criterion-referenced computerized test is expressed as a statistical hypothesis problem. This admits that it can be studied by using the theory of optimal design. The power function of the statistical test is used as a criterion function when designing the test. A formal proof is provided showing that all items should have the same item…

Bayesian network models offer a large degree of flexibility for modeling dependence among observables (item outcome variables) from the same task that may be dependent. This paper explores four design patterns for modeling locally dependent observations from the same task: (1) No context--Ignore dependence among observables; (2) Compensatory…

For two random variables, X and Y, let D = X - Y, and let theta[subscript x], theta[subscript y], and theta[subscript d] be the corresponding medians. It is known that the Wilcoxon-Mann-Whitney test and its modern extensions do not test H[subscript o] : theta[subscript x] = theta[subscript y], but rather, they test H[subscript o] : theta[subscript…

This study examined the robustness of the estimation of fixed-effects in multilevel analysis, as might occur in the conduct of school-effects studies with outlying schools. Outlying values for both intercepts and slopes for individual schools were modeled separately to determine the effects of extreme values of second-level variables on the…

A 2-to-the-kth-power mirror-image design is defined as one in which repeated observations of subjects occurs among the levels of a usual 2-to-the-kth-power design, but there is the restriction that no subject may receive a given level of any factor more than once. Such a restriction might arise, for example, if a subject's response is expected to…

This paper presents a method for estimating certain characteristics of test items which are designed to measure ability, or knowledge, in a particular area. Under the assumption that ability parameters are sampled from a normal distribution, the EM algorithm is used to derive maximum likelihood estimates to item parameters of the two-parameter…

Two order theoretic techniques were presented and compared. Ordering theory of Krus and Bart (1974) and an extended Takeya's item relational structure analysis (IRS) by Tatsuoka and Tatsuoka (1981) were used to extract the hierarchical item structure from three datasets. Directed graphs were constructed and both methods were assessed as to how…

Canonical correlation analysis is a powerful statistical method subsuming other parametric significance tests as special cases, and which can often best honor the complex reality to which most researchers wish to generalize. However, it has been suggested that the canonical correlation coefficient is positively biased. A Monte Carlo study…

Provides examples of the use of computer simulation to help beginners develop a grasp for difficult statistical concepts. The implementation of this teaching methodology is discussed and analysis of simulation output through use of standard statistical software packages is illustrated. (Author/MBR)

Reports survey results on statistical characteristics and adequacy of random number generators on microcomputers. Cycle size, seed, and operational time considerations, and statistical tests examining validity of generators are discussed. Evaluations of software for specific microcomputers are presented. Experiments which demonstrate dangers of…

A game simulating an Einstein model of a crystal producing a Boltzmann distribution. Computer-made films present the results with large distributions showing heat flow and some applications to entropy. (TS)

The evidence indicates that a computer-based business game in the policy course is useful to the teacher, the student, and the graduate on the job. (Author)

Describes an experiment from a physical chemistry course that consists of a computer simulation of throwing dice and the statistics involved. The experiment is designed to improve students' understanding of statistical evaluation of experimental data and to introduce programming techniques. (DDR)