Technology and, in particular, computer algebra systems, allows us to change both the way we teach mathematics and the mathematical curriculum. Curiously enough, unlike what happens with linear system solving, algebraic system solving is not widely known. The aim of this paper is to show that, although the theory lying behind the "exact…

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.…

Twenty-three different methods of cluster analysis were compared in a four-stage sequential validation design. Results demonstrated that the solution given by Ward's method of cluster analysis was particularly powerful in comparison to solutions yielded by other techniques. (Author/JKS)

The purpose of this paper is to examine the validity of regression estimates when skewed dichotomous scales are used as independent variables. When Pearson product-moment correlations are used to measure zero-order associations involving dichotomous variables, the resulting coefficients underestimate the true associations. As a result, using…

Argues that H. W. Marsh and K.-T. Hau (1996) misunderstood parsimony and its role in testing a hypothesis about an incompletely specified model to establish its objective validity. More parsimonious models represent more complete hypotheses having more ways of being tested and confirmed. Marsh and Hau could also have used more parsimonious…

The runs test for random sequences of responding is proposed for application in long inventories with dichotomous items as an index of sterotyped responding. This index is useful for detecting whether the client shifts between response alternatives more or less frequently than would be expected by chance. (LMO)

This study examines the relationship between high-stakes school accountability and its effects upon student test scores and school policies. The authors seek to understand the extent to which accountability sanctions and incentives for the poorest-performing schools in Florida explain subsequent changes in school practices and policies as well as…

This paper empirically and systematically assessed the performance of bootstrap resampling procedure as it was applied to a regression model. Parameter estimates from Monte Carlo experiments (repeated sampling from population) and bootstrap experiments (repeated resampling from one original bootstrap sample) were generated and compared. Sample…

Examines assumptions underlying the employment of group means in communication research. Suggests a sample mean cannot be assumed to be a "good" statistic when the response vector represents different individuals' outcomes versus different outcomes of an individual. Notes implications for communication research. (SR)

The nature of the criterion (dependent) variable may play a useful role in structuring a list of classification/prediction problems. Such criteria are continuous in nature, binary dichotomous, or multichotomous. In this paper, discussion is limited to the continuous normally distributed criterion scenarios. For both cases, it is assumed that the…

The need for using invariance procedures to establish the external validity or generalizability of statistical results has been well documented. Invariance analysis is a tool that can be used to establish confidence in the replicability of research findings. Several approaches to invariance analysis are available that are broadly applicable across…

Methods for selecting relevant and appropriate quasi-experimental studies for inclusion in research synthesis using the threats-to-validity approach are presented. Effects of including and excluding studies are evaluated. (BS)

A dichotomous dependent variable is used to determine a combination of variables that will predict group membership. Dichotomous variables are frequently encountered in multiple regression analysis. However, several textbooks question the appropriateness of using multiple regression analysis when analyzing dichotomous dependent variables. The…

This report presents the results of a two-year project to design, pretest, and revise the Statistical Survey of Elementary Schools, which is intended to provide information on federally funded elementary education programs operating in local public school systems. The report also documents the activities and decisions that brought about these…

Intraclass correlation reliability estimates are based on the assumption that the various measures are equivalent. Joreskog's (1970) general model for the analysis of covariance structures can be used to test the validity of this assumption. (For related document, see TM 002 301.) (Author)