In 1881, Donald MacAlister posed a problem in the "Educational Times" that remains relevant today. The problem centers on the statistical evidence for the effectiveness of a treatment based on a comparison between two proportions. A brief historical sketch is followed by a discussion of two default Bayesian solutions, one based on a…

In this article, a Bayesian model selection approach is introduced that can select the best of a set of inequality and equality constrained hypotheses for contingency tables. The hypotheses are presented in terms of cell probabilities allowing researchers to test (in)equality constrained hypotheses in a format that is directly related to the data.…

A previously proposed model for memory based on neurophysiological considerations is reviewed. It is extended by introducing positive feedback of a set of neurons onto itself and allowing the neurons to saturate. The resulting model is analyzed by distinctive features, categorical perception, and as it applies to probability learning. (Editor/RK)

The three-parameter logistic model by Birnbaum for the multiple-choice item in the latent trait theory is considered with respect to the item response information function and the unique maximum condition. (Editor/RK)

A probabilistic unfolding model is presented which makes it possible to scale stimuli and subjects simultaneously, without assumptions concerning the distribution of subject or of stimuli. The applicability of the model is demonstrated in areas of attitude measurement where the assumption of normality is inadequate. (Editor)

This paper presents a procedure for estimating J scale (latent continuum) probabilities given a set of I scales (preference judgements). (Editor/RK)

Examines the main mathematical approaches to information retrieval, including both algebraic and probabilistic models, and describes difficulties which impede formalization of information retrieval processes. A number of developments are covered where new theoretical understandings have directly led to improved retrieval techniques and operations.…

Discusses models for the distribution of words in text and proposes a new model based on clustering that can be used to estimate the probability that a document contains a particular word as well as the number of distinct words in a document. Zipf's law and the Poisson approximation are also discussed. (18 references) (LRW)

Describes a statistical model that can predict, throughout the fiscal year, the amount of money that will be spent on firm orders against a given fund, thereby predicting the number of orders that must still be placed to totally spend but not overspend that fund. Data tables are included. (Author/JD)

The relative power of the Mann-Whitney statistic, the t-statistic, the median test, a test based on exceedances (A,B), and two special cases of (A,B) the Tukey quick test and the revised Tukey quick test, was investigated via a Monte Carlo experiment. These procedures were compared across four population probability models: uniform, beta, normal,…

In a nonmetric multiple-cue probability learning task involving 2 binary cue dimensions, it was found that Ss can learn to use configural or pattern information (a) when only the configural information is relevant, and in addition to the configural information, one or both of the cue dimensions are relevant. (Author/RK)

Reports information retrieval experiments comparing the performance of a probabilistic retrieval model that incorporates interdocument links with the simpler spreading activation strategy. Results indicated that the overall improvement obtained by including hypertext links in the retrieval model was low. (30 references) (EA)

Describes probabilistic document retrieval systems as a sequential learning process, in which the system learns the parameters of probability distributions describing the frequencies of feature occurrences in relevant and nonrelevant documents. Several techniques for estimating the parameters of distributions are described and the results of tests…

This study used a logistic probability model to investigate the effects of variables relating student characteristics and institutional factors on the decision to apply to a large land-grant research university. The study used the entire data set from American College Testing (ACT) program test-takers in the fall of 1995 and institutional data on…

DYNAMOD II IS A COMPUTERIZED MARKOVIAN-TYPE FLOW MODEL DEVELOPED TO PROVIDE ESTIMATES OF THE EDUCATIONAL POPULATION OF STUDENTS AND TEACHERS OVER SELECTED INTERVALS OF TIME. THE POPULATION IS CROSS-CLASSIFIED INTO 108 GROUPS BY SEX, RACE, AGE, AND EDUCATIONAL CATEGORY. THIS NOTE DESCRIBES THE METHODOLOGY USED IN DYNAMOD II, COMPARES DYNAMOD II…