A method for introducing ideas of probability theory is presented. The method is illustrated by solving a coin tossing" problem. (FL)

A mathematical model is used to justify having the Library of Congress do as much as possible of all the original cataloging for U.S. libraries. It is suggested that the potential savings due to decreased duplication of effort by local libraries could easily justify the use of a computer system at LC. (Author/JB)

Using constraints with cluster analysis limits the possible number of clusters. This paper deals with clustering problems where grouping is constrained by a symmetric and reflexive relation. Two approaches, along with illustrations, are presented. (Author/JKS)

A general class of nonhierarchical clustering models and associated algorithms for fitting them are presented. These models generalize the Shepard-Arabie Additive clusters model. Two applications are given and extensions to three-way models, nonmetric analyses, and other model specifications are provided. (Author/JKS)

The problem of characterizing the manifest probabilities of a latent trait model is considered. The approach taken here differs from the standard approach in that a population of examinees is being considered as opposed to a single examinee. Particular attention is given to the Rasch model. (Author/JKS)