A revised theory of consumer choice is used to analyze the economic aspects of the medical care market. (BH)

Describes a mathematical model used in statistical prediction. Model is derived from known independent continuously variable quantities having the same distribution. (RS)

The Popperian view has had, and continues to have, a remarkable influence on the development of economics and on what economists do. Examined are the hypothetico-deductive method and the role and nature of empirical testing. (RM)

The notion of multidimensional structure is discussed within the framework of an additive component model of multidimensional scaling, where a configuration is considered to be composed of disjoint subspaces, each one of which reflects variation due to a specific stimulus component. Empirical examples are given. (Author/BW)

The multivariate stochastic processes associated with the Marshall-Olkin multivariate exponential distribution are shown to be able to generate several models of similarity or preference data in the literature. (JKS)

Milligan presented the conditions that are required for a hierarchical clustering strategy to be monotonic, based on a formula by Lance and Williams. The statement of the conditions is improved and shown to provide necessary and sufficient conditions. (Author/GK)

Johnson has shown that the single linkage and complete linkage hierarchical clustering algorithms induce a metric on the data known as the ultrametric. Johnson's proof is extended to four other common clustering algorithms. Two additional methods also produce hierarchical structures which can violate the ultrametric inequality. (Author/CTM)

A revised theorem is presented concerning uniqueness of minimum rank solutions in common factor analysis. (Author)

Various types of finite mixtures of confirmatory factor analysis models are proposed for handling data heterogeneity. Proposed classes of mixture models differ in their unique representations of data heterogeneity, and three sampling schemes for these mixtures are distinguished. Advantages of the Approximate Scoring method are outlined. (SLD)

The Schmid-Leiman (J. Schmid and J. M. Leiman, 1957) decomposition of a hierarchical factor model converts the model to a constrained case of a bifactor model with orthogonal common factors that is equivalent to the hierarchical model. This article discusses the equivalence of the hierarchical and bifactor models. (Author/SLD)

The idea of test consistency is illustrated, with reference to two sets of test scores. A mathematical model is used to explain the relative consistency and relative inconsistency of measurements, and a means of indexing reliability is derived using the model. Practical aspects of estimating reliability are considered. (TJH)

A theorem is developed to show that the Kruskal-Wallis test (W. Kruskal and W. Wallis, 1952) (KWt) can be used validly to test a hypothesis about location under much less restrictive conditions than required by the recently accepted, mathematically correct shift model. The specific null hypothesis for which the KWt can be used validly is…