Each ellipse and hyperbola has a circle associated with it called the director circle. In this article, the author derives the equations of the circle for the ellipse and hyperbola through a different approach. Then the author concentrates on the director circle of the central conic given by the general quadratic equation. The content of this…

Hypotheses that do not have the standard bilinear form theta=CBM=0 occur naturally in the analysis of repeated measurement designs. An expanded class of the tests of the form psi=Tr(G theta)=0, called extended linear hypotheses, provides a richer class of parametric functions. A method to analyze double multivariate and mixed multivariate models…

Methods for the path analysis of complex (i.e., not fully recursive) causal models are briefly discussed. A computer program which simplifies analysis of such models and provides an option for automatically deleting marginal paths is described. (Author)

This article is divided into three main sections. The first addresses the problems associated with the present use of the linear model. The second provides some empirical evidence to help strengthen the arguments made against the model, and the third offers some alternatives along with suggestions for their implementation. (Author/DEP)

The binary search scheme is a method of finding a particular file from a set of ordered files stored in a computer. In this article an exact expression for the expected number of passes required to find a file is derived. (Author)

Gives a model to interrelate the measures of service used in a library. (Author/PF)

The use of indices of speededness in tests is reviewed and three possible indices which derive from a model which assumes that rate of work is normally distributed is proposed. Each of these indices is seen as limited by the failure to adequately consider the correlation between speed and power, but they have the advantage that they are derivable…

The defining property of an admissible scoring system is that any individual perceives himself as maximizing his expected score by reporting his true subjective distribution. The use of admissible scoring systems as a measure of probabilistic forecasts is becoming increasingly well-known in those cases where the forecast is a discrete distribution…

Presents a mathematical model of an information retrieval system thought to be general enough to serve as an abstract representation of most document and reference retrieval systems. The model is made up of four components that, in one form or another, appear in every functioning system. (Author)

The purpose of this study is to develop statistical tests for within cluster homogeneity when objects are scored on binary variables. (DEP)

The outbreak of research on "anomalous water," or "polywater," from 1962 to 1974 provides an interesting opportunity for testing the epidemic theory of idea dissemination. (Author)

Nothing short of advanced calculus can reduce coaching success to a formula, if, indeed, it can be done at all. (Author/MJB)

A model of user behavior in demand for library documents based on the economic theory of supply and demand is presented. (KP)

A paradoxical implication of Kraemer's expression for the large-sample standard error of Brogden's form of the biserial correlation is identified, and a new expression is given which does not imply the paradox. However, numerical evidence is presented which calls into question the correctness of the expression. (Author)

An alternative derivation is given for a generalization of the Rasch model which incorporates a guessing parameter. The probability of a correct response to the problem is a projective transformation of the problem difficulty. The ability and difficulty parameters separate into additive components. (Author/JKS)