Tau, Lambda, and Kappa are measures developed for the analysis of discrete multivariate data of the type represented by stimulus response confusion matrices. The accuracy with which they may be estimated from small sample confusion matrices is investigated by Monte Carlo methods. (Author/LMO)

Conjunctive item response models are introduced such that: (1) sufficient statistics for latent traits are not necessarily additive in item scores; (2) items are not necessarily locally independent; and (3) existing compensatory (additive) item response models including the binomial, Rasch, logistic, and general locally independent model are…

The problem of managing the reserve of cobalt is presented, followed by a method for bringing the stockpiled amount from any level to a desired goal. Solving a stochastic programming problem is involved. The procedure is discussed in detail. (MNS)

A Bayesian procedure is developed for the estimation of parameters in the two-parameter logistic item response model. Joint modal estimates of the parameters are obtained and procedures for the specification of prior information are described. (Author/LMO)

Discusses the use of computer programs in science and mathematics. Provides examples of how computation offers a new means of describing and investigating scientific and mathematical systems and how computer simulation can be used to examine new kinds of models for natural phenomena. (JN)

A five by five covariance matrix representing longitudinal measurements at five occasions is used to illustrate that markedly different types of learning curves may generate indistinguishable covariance structures. An excellent fit of a simplex structure can be misleading. Common uses of covariance structure models for growth studies are…

Drawing on recently developed methodology for structural equation modeling with categorical data, this article proposes a new approach for investigating the behavior of dichotomously scored test items in relation to other relevant (observed) variables. A linear structural model relates the latent ability variable to a set of observed scores.…

Contrasts artificial behavior with artificial intelligence, traces Law of Effect's development from a verbal statement into a mathematical model providing algorithms for artificial behavior programs, and describes an attempt to use computer graphics and animation to simulate behavior and teach abstract concepts. (MBR)

Presents algorithms for the simulation and motion display of the three basic kinematic devices: (1) four bar linkages; (2) the slider crank; and (3) the inverted slider crank mechanisms. The algorithms were implemented on a Commodore-VIC 20 microcomputer system with 6500 bytes of available memory. (Author/JN)

Monitoring student performance on microcomputer drill and practice programs over time provides evidence that students learn from the programs at different rates and that programs differ in the rates at which they impart learning to students. Implications of these and other findings for science teaching are addressed. (JN)

This study involved 179 9-year-olds and 352 13-year-olds in New Zealand. Four addition and four subtraction tasks were set to ascertain students' ability to use the number line. Comparison of these data with results from the national assessment in the United States are given. (MNS)

The concept of change is related to suppressor variable conditions in a least square regression model. The domain of conditions necessary for a weighted change score composite to emerge as an underlying construct is mapped and the information loss through arbitrary assignment of weights to a change composite is explored. (Author/BW)

Prediction of success in a special program often guides program participant selection and treatment. If the statistical analysis used to develop such predictions is based on the special selectivity built into the program, the predictions can be misleading and the validation tests uninformative. Federal district court pretrial release data is used…

Sex differences in speed of solving mental rotation problems were replicated but college men and women were alike in frequency of use of algorithms to solve problems. The most frequent algorithm involved encoding stimuli in working memory, mental rotation of one to orientation of the other, comparison, and response. (Author/RD)

Twelve structural models of similarity were fitted to data from conventional and computer adaptive test (CAT) batteries measuring the same aptitude in a double cross-validation design. Three of the 12 models, including a multiplicative structure model, performed well, providing support for using CATs as replacements for conventional tests. (NSF)