In true experiments in which sample material can be randomly assigned to treatment conditions, most researchers presume that the condition of equal sample sizes is statistically desirable. When one or more a priori contrasts can be identified which represent a few overriding experimental concerns, however, allocating sample material unequally will…

By employing a concomitant variable, researchers can reduce the error, increase the precision, and maximize the power of an experimental design. Blocking and analysis of covariance (ANCOVA) are most often used to harness the power of a concomitant variable. Whether to block or covary and how many blocks to be used if a block design is chosen…

In order to examine the possible effects of violation of assumptions using parametric procedures, this study is an exploratory investigation into the use of parametric versus nonparametric procedures using a multiple case study design. The case study investigation guidelines outlined by Yin served as the methodology. The following univariate…

298 EDUCATIONAL AND PSYCHOLOGICAL RESEARCH PAPERS PUBLISHED IN 5 JOURNALS DURING 1966-67 WERE CLASSIFIED ON THE BASIS OF SPONSORSHIP, AUTHORS' GENERAL INTENTIONS, DESIGN, ASSUMPTIONS, AND ANALYSIS. ADVANCES IN STATISTICAL THEORY (INCLUDING WORK ON GENERAL ANALYSIS OF VARIANCE DESIGNS, HYPOTHESIS TESTING IN FACTOR ANALYSIS, MULTIVARIATE ANALYSIS,…