Two theorems concerning F in analysis of covariance with two groups (experimental and control) and one covariable (pretest score) are presented. The first shows explicitly that F is a direct function of the ratio of the variance about the regression line for the total sample to the variance about the within-group regression line. The second…

A program obtained random samples from known populations, some of which violated the homogeneity assumption. Student t tests and Mann-Whitney U Tests were performed on the sample value. Where the t test led to incorrect decisions, the use of Mann-Whitney U test in its place led to poorer results. (JAZ)

Statistical measures of practical significance report the extent to which variation in the dependent variable can be explained by the independent variable. Reports of special education research sometimes discuss practicality using the estimate of statistical significance. Practical significance, however, may vary greatly among samples even though…

This study of 50 pairs of popular (written for layman) and technical (designed for those having specialized knowledge in particular discipline) monographs matched by subject, date of publication, and date of acquisition indicates that although technical works circulated more than popular, difference was not statistically significant. Seven…

This study describes (a) potential mathematics education leaders' professional development experiences, awareness, beliefs, and attitudes and (b) the subsequent changes in these constructs as they participated in a leadership development program. The context of the professional development was a three-week institute and a year-long follow-up. The…

In their 2004 paper "The role of Advanced Placement and honors courses in college admissions," (see ED492533) Saul Geiser and Veronica Santelices of the University of California, Berkeley, addressed the use of Advanced Placement Program (AP) and honors courses as a criterion for admission at the University of California system and…

Concludes that double spaced reading materials with verified right hand margins had a desirable effect on comprehension for a population of educable mentally retarded pupils. (RW)

It is shown that using formulae for the estimation of sampling errors based on simple random sampling, when a design actually involves cluster sampling, can lead to serious underestimation of error. Jackknife and balanced repeated replication are recommended as techniques for dealing with this problem. (Author/CTM)

Arguing that reliable and valid dropout rate estimates are prerequisite to establishment of causal factors and intervention programs, this article examines differences in definitions of dropouts, computational methods, and the complexities in defining cohorts, as well as the importance of sample attrition. Several sources of error are discussed.…

The use of statistical methods to combine the results of independent empirical research studies (metanalysis) has a long history, with work mainly divided into tests of the statistical significance of combined results and methods for combining estimates across studies. Methods of metanalysis and their applications are reviewed. (SLD)

An extension is proposed for the network algorithm introduced by C.R. Mehta and N.R. Patel to construct exact tail probabilities for testing the general hypothesis that item responses are distributed according to the Rasch model. A simulation study indicates the efficiency of the algorithm. (SLD)

Different approaches to defining suppression in multiple regression/correlation are compared, and their differences are illustrated. A test for determining the significance of a suppressor effect, which is based on the definition of suppression of W. F. Velicer, is extended to the general multiple predictor case and analysis of variance. (SLD)

Two issues in analysis of interactions in complex linear models are considered. One is the omnibus test for interaction, and the other concerns follow-up tests when the omnibus test is significant. Reconsidered omnibus and follow-up tests are illustrated on an educational data set analyzed using the Statistical Analysis System. (SLD)

Offers a framework for remedying some of the problems associated with the use of statistical significance tests through modifying journal editorial policies. Reviews examples from some journals that have established guidelines for reporting results of statistical significance tests. (SLD)

Presentation of quantitative research on the family often suffers from a tendency to interpret findings on a statistical rather than substantive basis. Advocates the use of data analysis that lends itself to an intuitive understanding of the nature of the findings, the strength of the association, and the import of the result. (JPS)