JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology andâ€¦ (More)

The two main types of interaction between any pair of biological species, which are of most interest to the ecologist, are either when they are competing together for some common source of foodâ€¦ (More)

Consider N entities to be classified (e.g., geographical areas), a matrix of dissimilarity between pairs of entities, a graph H with vertices associated with these entities such that the edges joinâ€¦ (More)

This paper is about Guttman's method for assigning optimal numerical scores to categorical variables, and related methods, which underlie Healy's TW1 and TW2 bone-age standards. In giving theâ€¦ (More)

We consider the problem minx(xâˆ’t)â€²A(xâˆ’t) subject to xâ€²Bx+2bâ€²x = k where A is positive definite or positive semidefinite. Commonly occurring statistical variants of this problem are discussed withinâ€¦ (More)

A simple geometry allows the main properties of matrix approximations used in biplot displays to be developed. It establishes orthogonal components of an analysis of variance, from which differentâ€¦ (More)

The set of Euclidean distance matrices has a well-known representation as a convex cone. The problems of representing the group averages of K distance matrices are discussed, but not fully resolved,â€¦ (More)