Models relating individual and group problem solving solution times under the condition of limited time (time limit censoring) are presented. Maximum likelihood estimation of parameters and a goodness of fit test are presented. (Author/JKS)

Three dimensional contingency tables in which one variable is considered to be a factor and the other two variables have a natural relationship (such as left and right eye vision) are analyzed. Models involving symmetry and proportional symmetry between the related variables are also presented. (Author/JKS)

A mathematical model of a regional interlibrary loan system was developed as a tool for the design and evaluation of a strategy to equalize the load of Interlibrary Loans (ILL) of libraries in the system. The load-leveling capability of several algorithms for representing each library's ILL activity was tested. (Author/VT)

The purpose of this investigation was to test extensions of a model of concept learning. The investigators examined the applicability of a mathematical model to the learning of selected science concepts. Findings suggest that certain extensions of the model may apply for a complex concept identification task. (Author/MA)

Statistical tests for determining whether one pole of an attitude scale is characteristic of a population are examined. A less restrictive procedure and the situations in which it might be used are discussed. (Author/JKS)

Solutions for the indeterminate common factor of a group of variables satisfying the single common factor model are not unique. This paper examines a number of thereoms concerning that problem and draws conclusions from them for factor analysis in general. (Author/JKS)

This research simulated responses of 75 subjects to 30 items under the Birnbaum model and attempted a fit to the data using the Rasch model. When item discriminations varied from a variance of .05 to .25, there was only a slight increase in lack of fit as the variances increased. (Author/CTM)

Two studies are reviewed which concern the analysis and use of attitudinal data to further enhance the understanding of urban travel. Both studies employed multidimensional scaling techniques. (Author/MA)

The students in a basic course on probability and statistics in Trinidad demonstrated that the number of fatal highway accidents appeared to follow a Poisson distribution while the length of time between deaths followed exponential distribution. (MN)

Methods for estimating the mean and variance of latent ability parameters of a normally distributed population that has been tested with Rasch model-calibrated test items are discussed. Methods for checking the normality of the population are also included. (JKS)

Urry's procedure for approximating latent trait test models is shown to tend to underestimate item discriminatory power and overestimate item difficulty. A method for correcting these biases is provided, and implications of the procedures are discussed. (Author/JKS)

Presents a mathematical model for simulating a newspaper financial system. Includes the effects of advertising and circulation for predicting advertising linage as a function of population, income, and advertising rate. (RL)

A problem illustrating how physics and mathematics complement one another when analyzing problems of the physical world is described. (JT)

Examines the concept of PdV work and the harmonic oscillator as an example of a thermodynamic system with properties analogous to an ideal gas. (SL)

A method is described to help identify important groups in an organization, rank their probable actions, and arrive at a list of the most important group-action pairs for that company. Available from: The Institute of Management Sciences, 146 Westminister Street, Providence, Rhode Island 02903.