The Auto-Regressive Integrated Moving Average (ARIMA) Models, often referred to as Box-Jenkins models, are regression methods for analyzing sequential dependent observations with large amounts of data. The Box-Jenkins approach, a three-stage procedure consisting of identification, estimation and diagnosis, was used to select the most appropriate…

An alternative definition has been developed of the delta scale of item difficulty used at Educational Testing Service. The traditional delta scale uses an inverse normal transformation based on normal ogive models developed years ago. However, no use is made of this fact in typical uses of item deltas. It is simply one way to make the probability…

The models and procedures discussed in this paper are related to those presented in Bock and Aitkin (1981), where they considered the 2-parameter probit model and approximated a normally distributed prior distribution of abilities by a finite and discrete distribution. One purpose of this paper is to clarify the nature of the general EM (GEM)…

A sample of 24 subjects was presented with 800 addition problems to test a general model of simple and complex addition. According to this model, an addition problem is encoded and verified by column, with specific addition strategies determined by the size of the problem. Two hundred problems each of the following four types were presented: (1)…

Children learn arithmetic procedures by rote, rather than by constructing them with an understanding of numbers. Rote learning produces lack of flexibility, nonsensical errors, and other difficulties. Proposed is a theory of conceptual understanding and its role in learning and executing arithmetic procedures. The basic hypothesis is that…

This proposal attempts to follow in Allan Birnbaum's tradition by using Bayesian ideas to show that his mental test model possesses even broader applicability than previously realized. Birnbaum's two significant contributions to the theories of statistics and educational testing are: (1) the proof that the sufficiency and conditionality principles…

The purpose of this paper is to present a generalization of the concept of item difficulty to test items that measure more than one dimension. Three common definitions of item difficulty were considered: the proportion of correct responses for a group of individuals; the probability of a correct response to an item for a specific person; and the…

Two articles describe a model for processing natural-language queries in information retrieval systems. Part I proposes a language interface based on fuzzy set techniques to handle the uncertainty inherent in natural-language semantics. Part II develops a model of the retrieval system and describes an implementation using a knowledge-based systems…

Describes the two basic approaches to the calculation of term discrimination values for automatic indexing. The results of an experiment that investigated the differences between algorithms of these two approaches in terms of their impact on the discrimination value model are reported and discussed. (13 references) (Author/CLB)

Focuses on the role of the computer system in group decision making. Two systems used in solving negotiating problems--NEGO and MEDIATOR--and three procedures that can be utilized to develop group decision support systems are analyzed, based on multicriteria decision analysis and mathematical programming models. (Author/LRW)

Develops a model of ideal minority representation to assess whether or not an employer's current personnel policies are consistent with a random hiring policy. The model is then applied to a case alleging sex discrimination in the hiring practices of a university academic department. Appended are 12 references. (MLF)

Correlation structure of the Burrell and Cane mixed Poisson model for library loans with aging is presented and illustrated by data from University of Sussex. The approach is compared and contrasted with that originally formulated by Morse and recently reevaluated by Beheshti and Tague. Directions for future investigations are suggested. (Author)

The relationship of minutes of reading instruction to the gains in reading performance for 3,374 elementary school children shows consistent positive findings between large- and small-group classroom instruction and reading gains. Some of the negative results for individualized instruction may be due to school assignment practices. (Author/MLF)

Review of recent developments in statistical theories for social sciences highlights Haitun's statistical distributions, Laplace's "Law of Succession" and distribution, Laplace and Bradford analysis of book-index data, inefficiency of frequency distribution analysis, Laws of Bradford and Zipf, natural categorization, and Bradford Law and…

Discusses the master equation of a stochastic model in chemical process systems. Presents a solution technique known as the System Size Expansion. (YP)