Discusses students' exploration of a particular rational function in the context of people waiting in line for service. The concepts of domain, range, and asymptotes are also developed in that context as is the effect of changes in input variables on function outputs. (Author/NB)

Examines the impact of a school-based assessment system on the implementation of an applications/modeling-based curriculum at the senior secondary level. The persistence of high task scaffolding in assessment tasks throughout the course and the concerns of teachers about the reliability and ownership of assessment in unsupervised conditions…

Developed a multidimensional Rasch model that is a multidimensional extension of item component models and determined relations to existing multidimensional item response theory models. Applied the model to a questionnaire on students' interest in physics to demonstrate that model parameters can be estimated even when 17 latent dimensions are to…

Reviews methods for handling missing data in a research study. Model-based methods, such as maximum likelihood using the EM algorithm and multiple imputation, hold more promise than ad hoc methods. Although model-based methods require more specialized computer programs and assumptions about the nature of missing data, these methods are appropriate…

A major pitfall with fixed-effects analysis of variance in the nested design is illustrated. Under the null hypothesis of no intervention effect, the rejection rate for "F(sub fixed)" in the nested design is greater than the putative Type I error rate of the test, potentially to an extreme degree. (Author/TJH)

Sixteen tables are presented for critical values of the larger of two sample correlation coefficients from two independent samples, given the sample size and the value of the smaller correlation. These tables allow quick assessment of significance without requiring calculation of the test statistic. (SLD)

A method based on three variance computations and some minor arithmetic is presented as an alternative to criterion-scale regression for the computation of a repeated measures-randomized blocks analysis of variance (RMBANOVA). The use of margin sum and cell variances can simplify the analysis of data for RMBANOVA. (SLD)

The problem associated with evaluating an econometric model using values outside those used in the model estimation is illustrated in the evaluations of a residential load management program during each of two successive years. Analysis reveals that attention must be paid to this problem. (Author/TJH)

Describes the Waller-Kraft "wish list" of desired information retrieval system properties and identifies ambiguities caused by two distinct uses of the phrase "query term weight." Examples of problems arising from the ambiguity are given and a new list is created and discussed. (10 references) (Author/CLB)

A general model is developed for the analysis of multivariate multilevel data structures. Special cases of this model include: repeated measures designs; multiple matrix samples; multilevel latent variable models; multiple time series and variance and covariance component models. (Author)

Manifest discrete time and latent Markov chain models are described, and the results given by each are compared for the re-analysis of a three-wave table of repeated behavior ratings of children. More recent developments in latent discrete time Markov chain modeling address the problems of the table more efficiently. (SLD)

Eight models that can be used to analyze data from a pretest-posttest design are discussed. Artificial data are used to demonstrate that comparisons among some of the models generate results identical to those obtained by using repeated analysis of variance measures. Such results are shown to be potentially misleading. (Author/TJH)

The problem of scaling ordinal categorical data observed over two or more sets of categories measuring a single characteristic is addressed. Scaling is obtained by solving a constrained entropy model. A Kullback-Leibler statistic is generated that operationalizes a measure for the strength of consistency among the sets of categories. (TJH)

A Bayesian approach to the testing of competing covariance structures is developed. Approximate posterior probabilities are easily obtained from the chi square values and other known constants. The approach is illustrated using an example that demonstrates how the prior probabilities can alter results concerning the preferred model specification.…

A general dichotomous condition is derived for the unidimensional polytomous Rasch model. The robustness of the dichotomous analysis is investigated in a simulation study. The model shows a close relation with the two-parameter Birnbaum model. (TJH)