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)

Several robust absolute deviation statistics have been developed recently. Two such correlation coefficients are developed and discussed, one for ranked data and another for interval level data. The standard error and range of the coefficients are given. The algebraic relationship between the coefficients and three widely used correlation…

Discusses the inconsistent and shifting ways in which the U.S. Census treats race, color, and ethnicity. Suggests that long-term conceptual frameworks be developed so that the next census will not produce uneven categories based on unequal assumptions. (EVL)

Addresses issue of range enhancement effects on correlations, asserting that, while adding to or deleting from sample can affect variance and correlation in sample, increases or decreases in individual differences in intact sample resulting from such factors as history, maturation, training, and experience will not necessarily affect correlations.…

James's second-order approximation for testing the equality of "k" independent means under heterogeneity of variance may be adapted to the test for the equality of "k" independent regression slopes under heterogeneity of error variance. Performance of the approximation is evaluated and availability of computer programs is…

Accuracy was compared for three methods of implementing parallel analysis with mean eigenvalues (regression, interpolation, and computation with three samples of random data). The accuracy of parallel analysis with 95th percentile eigenvalues (through regression and interpolation) was also considered. No evidence of differential accuracy emerged…

A procedure is presented to transform an n-dimensional scatter diagram into a two-dimensional scatter diagram while preserving proximity relationships between points. This procedure can help in the presentation and interpretation of multivariate results. (Author/SLD)

This article reviews and discusses the use of statistical concepts in a natural resources and life sciences journal on the basis of a census of the articles published in a recent issue of the "Agronomy Journal" and presents a flow chart and a graph that display the inter-relationships between the most commonly used statistical terms. It also…

The comparability of examinations in different subjects has been a controversial topic for many years and a number of criticisms have been made of statistical approaches to estimating the "difficulties" of achieving particular grades in different subjects. This paper argues that if comparability is understood in terms of a linking…

Researchers can evaluate learning by using direct and indirect assessment. Although there are various ways to apply these approaches, two common techniques are pretests and posttests (direct assessment), in which students demonstrate mastery of topics or skills, and the use of knowledge surveys (indirect assessment). The present authors used these…

This article explores the statistical methodologies used in demonstration and effectiveness studies when the treatments are applied across multiple settings. The importance of evaluating and how to evaluate these types of studies are discussed. As an alternative to standard methodology, the authors of this article offer an empirical binomial…

Using data to redesign instruction is a means of increasing student achievement. Educators in Camden County (Georgia) Schools have used data from benchmark testing since 1999. They hired a commercial vendor to design a benchmark test that is administered four times a year and use the data to generate subject-area reports that can be further…