The calculation of concentrations in the case of many simultaneous equilibria can be reduced to a search for a local minimum of a function of n variables, in which n denotes the number of mass balances involved. The method is simple and time-saving, but requires the availability of a computer. (author/BB)

A definition of a suppressor variable is presented which is based on the relation of the semipartial correlation to the zero order correlation. Advantages of the definition are given. (Author/JKS)

Path analytic techniques for assessing the validity of indicators in multitrait-multimethod matrices represent improvements on Campbell and Fiske's early procedures for testing for validity. The diagnosis of indicator ills by means of confirmatory factor analysis is especially useful. An empirical example of these techniques is presented.…

The concepts of elevation, scatter, and shape are investigated as parameters in assessing the similarity among profiles of individuals. A computational strategy for differentiating the independent contribution of each parameter to more global indices of resemblance is presented. (Author/JKS)

The imprecision of some concepts used in formal models in information science has led to attempts to apply fuzzy set theory to aspects of information science. An analysis of various kinds of imprecision that can occur indicates that fuzzy set theory is not an appropriate formalism for these models. (Author/MBR)

Path analysis is a data analytic technique for estimating the strengths of hypothesized relationships among a group of variables for a particular sample. Strategies for the use of path analysis are discussed in detail in this extensive article. (JKS)

The concepts of demand, need, desire, and take-up were discussed in the context of preschool services in three small areas of Inner London. It was shown by using log-linear models that desire for preschool provision could be efficiently predicted by a combination of sociodemographic variables. (Author/IRT)

Presents mathematical games that involve a problem-solving matrix, multicolored cubes, and three-dimensional dominoes. The work of Alexander MacMahon is highlighted. (MA)

Examines an alternative approach to analysis of chemical reactions. In this approach, a thermal entropy gradient is introduced. (MA)

The relationship between quantitative predictor variables and the probability of occurrence of one or more levels of a qualitative criterion variable can be analyzed by quantal response techniques. This paper presents and discusses two quantal response models, comparing them to multiple linear regression and discriminant analysis. (Author/JKS)

A procedure for obtaining Rasch model estimates of item difficulty and of ability is detailed. The procedure approximates the optimal but difficult to obtain "unconditional" estimates. (JKS)

An artifact encountered in regression models of human judgment is explored. The direction and magnitude of the artifactual effect is shown to depend upon the nature of the experimental task and task conditions. Use of an alternative index is recommended. (Author/JKS)

A general coefficient for tests, delta, is derived from a decision theoretic point of view. The situations are considered in which a true score is estimated by a function of the observed score, observed scores are split into more than two categories, and observed scores are split into only two categories. (Author/CTM)

An alternative formulation for Guttman scaling is presented. The new formulation is described, and advantages over Guttman's formulation are detailed. The method is assumption-free and capable of multidimensional analysis. (Author/JKS)

The strategy for investigating convergent and discriminant test validity, known as the multitrait-multimethod matrix, is investigated. A nonparametric significance testing procedure is suggested and demonstrated. (JKS)