A model that can be used to show the arrangement of light and heavy chains, disulfide linkages, domains, and subclass variations in antibodies is given. It can be constructed and modified to illustrate Fab, F(ab')2, and Fc fragments, single domain and bifunctional antibodies, and labeling of antibodies. (Author)

Used experimental driving simulator as basis for strategy to encourage a reduction in drunk driving prevalence using adult male subjects (n=36) who participated in a study group and controls (n=36). Results indicated study group subjects significantly decreased their drunk driving compared to the control group. (ABL)

The first of two articles discusses virtual reality (VR) and online databases; the second one reports on an interview with Thomas A. Furness III, who defines VR and explains work at the Human Interface Technology Laboratory (HIT). Sidebars contain a glossary of VR terms and a conversation with Toni Emerson, the HIT lab's librarian. (LRW)

How item bias indexes based on item response theory (IRT) identify bias that results from multidimensionality is demonstrated. Simulation results suggest that IRT-based bias indexes detect multidimensional items with bias but do not detect multidimensional items without bias. They also do not confound between-group differences on the primary test.…

McAteer discusses how simulations can provide rich learning environments and explains how to design behavioral simulations. MacDonald describes the use of the listening vignette in workshops on listening skills. (JOW)

Applications of the confirmatory factor analysis block-diagonal model to published data on 18 multitrait-multimethod matrices were reviewed to show widespread estimation problems. Possible causes of estimation difficulties were explored using computer simulations. These problems make the block-diagonal approach less useful than has generally been…

Simulations show effects of variability on the maximum contingency that can be displayed by an average 2 X 2 table. Results help explain the regularity known as the Tulving-Wiseman law, as well as conditions under which exceptions are found. Dangers posed by variability and Simpson's paradox are discussed. (SLD)

Proposes a two-stage estimation method for the analysis of covariance structure models with ordinal ipsative data (OID). A goodness-of-fit statistic is given for testing the hypothesized covariance structure matrix, and simulation results show that the method works well with a large sample. (SLD)

Presents a simulation activity in which students assume the role of grizzly bears in Banff National Park. Concepts such as species diversity, fitness, natural selection, habitat loss, extinction, and population dynamics are discussed. Children learn how human activities can affect the bear's reproductive success. Lists materials, instructional…

Investigated the effectiveness of H. Wainer's (1993) strategy for obtaining positively biased ability estimates when examinees can review and change answers on computerized adaptive tests. Results, based on simulation and testing data from 87 college students, show that the Wainer strategy sometimes yields inflated ability estimates and sometimes…

Investigated the performance of the Poly-DIMTEST (PD) procedure (and associated computer program) in assessing the unidimensionality of test data produced by polytomous items through Monte Carlo simulation. Results show that PD can confirm unidimensionality for unidimensional simulated data and can detect lack of unidimensionality. (SLD)

Examines the relationship between Cronbach's coefficient alpha and the reliability of a composite of a prespecified set of interrelated nonhomogeneous components through simulation. Shows that alpha can over- or underestimate scale reliability at the population level. Illustrates the bias in terms of structural parameters. (SLD)

Describes four procedures previously developed for estimating conditional standard errors of measurement for scale scores and compares them in a simulation study. All four procedures appear viable. Recommends that test users select a procedure based on various factors such as the type of scale score of concern, test characteristics, assumptions…

Describes how the simulation of Mars settlement is conducted in a class at Northern Arizona University and discusses the pedagogical and anthropological premises involved. The course requires students to use both halves of their brains, to use technology creatively, and to bind creativity to technological feasibility. (MMU)

The behavior of eight measures of fit used to evaluate confirmatory factor analysis models was studied through Monte Carlo simulation to determine the extent to which sample size, model size, estimation procedure, and level of nonnormality affect fit when analyzing polytomous data. Implications of results for evaluating fit are discussed. (SLD)