Mathematical models in which operators are used are described. (DB)

A model for the utility of gambling that is based on Von Neumann-Morgenstern utility theory is proposed and analyzed. Aspects of the utility of gambling are noted, and comparisons are made to standard concepts of risk attitudes. (Author/JKS)

The use of these three model selection information criteria for latent class models was studied for nonnested models: (1) Akaike's information criterion (H. Akaike, 1973) (AIC); (2) the Schwarz information (G. Schwarz, 1978) (SIC) criterion; and (3) the Bozdogan version of the AIC (CAIC) (H. Bozdogan, 1987). Situations in which each is preferable…

Presents a generalization and improvement for the definition proposed by E. Dzhafarov (2001) for selectiveness in the dependence of several random variables on several (sets of) external factors. This generalization links the notion of selective influence with that of conditional independence. (SLD)

Explored the use of additive tree models to represent set-symmetric distances for feature arrangements in set-theoretic or feature models. Studied arrangements of feature sets that have been proposed to represent qualitative and quantitative variation among objects in situations in which feature structures are defined in various ways. (SLD)

Recent attempts have been made to find a robust method for comparing the variances of "J" dependent random variables. However, these procedures can give unsatisfactory results. Several new procedures that are derived heuristically are examined. The most effective method is based on the statistic derived by D. Quade. (TJH)

Presents a version of the nonlinear mixed-effects model that allows random effects only on the linear coefficients, and in which nonlinear parameters are not stochastic. Highlights the flexibility of the model and illustrates features through two examples. (SLD)

Presents a method for estimating the random coefficients model using covariance structure modeling and allowing one to estimate both fixed and random effects. The method is applied to real and simulated data, including marriage data from J. Belsky and M. Rovine (1990). (SLD)

General formulas are derived for assessing local influence under restrictions in which the first derivatives are still zeros, and then these results are applied to factor analysis, as the usually used restriction in factor analysis satisfies the conditions. (SLD)

Studied the order-statistics models, extending the usual normal order-statistics model into one in which the underlying random variables followed a multivariate normal distribution. Used a Bayesian approach and the Gibbs sampling technique. Applied the proposed method to analyze presidential election data from the American Psychological…

Discusses , in the context of confirmatory latent class analysis, model selection using Bayes factors and (pseudo) likelihood ratio statistics. Uses a small simulation study to show that in this context, Bayes factors and the pseudo likelihood ratio statistics have the best properties. (SLD)

Assessed the extent to which results in exploratory factor analysis (EFA) studies can be replicated by confirmatory factor analysis in the same sample. Used 10 factor structures drawn from the literature. Results show that confirmatory factor models in which all low EFA pattern coefficients were fixed to zero fitted especially poorly. (SLD)

Many institutions regularly conduct surveys of students. In some cases these provide descriptive statistics about students' actual use of course components and the descriptive statistics are discussed using ordinary language. A number of refinements to these surveys are proposed. It is argued that mathematical modeling as used in the discipline of…

P. J. Kellman, P. Garrigan, and T. F. Shipley's theory of 3-dimensional object interpolation asserts that existing data, as well as logical considerations, support the view that an identical contour interpolation process underlies the interpolation of partially camouflaged and partially occluded objects (modal completion and amodal completion,…

Papini and Pellegrini (Papini, M. R., & Pellegrini, S. "Scaling relative incentive value in consummatory behavior." "Learning and Motivation", in press) observed that, within limits, the level of consummatory responding of rats exposed to incentive downshifts in the concentration of sucrose solutions was similar when the ratio of test/training…