In traditional null hypothesis testing, researchers use critical values of various test statistics in order to minimize the risk of making Type I errors. These critical values are associated with common alpha levels (e.g., 0.01, 0.05) that indicate the probability of a Type I error. Alpha values are set at conservative levels such that the Type I…

A specialized vector used to interpret rejected multivariate single sample hypotheses, introduced in an earlier article by the writer (EJ 097 103), is shown here to be equivalent to the vector that would be obtained if discriminant analysis techniques were to be applied to a single sample problem. (Author)

Kendall's S is often used for measuring magnitude of bivariate association in social and behavioral research. This nomogram permits a research analyst to make rapid and accurate evaluation of the statistical significance of S without recourse to formulae or computations in all except borderline cases. (Author/CTM)

When analyzing a squared multiple correlation coefficient, an investigator may be interested in determining whether it is above or below a known constant, rather than testing the null hypothesis. This paper gives the sample sizes required for answering this question when indifference zone formulation of the problem is used. (Author/BW)

A walk through Milne's Enchanted Forest leads to an unexpected encounter with hypothesis testing.

Educational films for children aim to impart knowledge about a certain topic. In the present paper, it is investigated how much and what kind of information children can remember from educational films and how knowledge acquisition through films could be enhanced. The studies described here were designed to test the hypothesis that children's…

Over the past three decades, U.S. science policy has shifted from decentralized support of small, investigator-initiated research projects to more centralized, block grant-based, multidisciplinary research centers. No matter one's take on the "revolutionary" nature of this shift, a major consequence is that university scientists, now more than…

The major objective of this study was to investigate the effects of non-normality on Type III error rates for ANOVA F its three commonly recommended parametric counterparts namely Welch, Brown-Forsythe, and Alexander-Govern test. Therefore these tests were compared in terms of Type III error rates across the variety of population distributions,…

IQ test scores have risen steadily across the industrialized world ever since such tests were first widely administered, a phenomenon known as the Flynn effect. Although the effect was documented more than 2 decades ago, there is currently no generally agreed-on explanation for it. The author argues that the phenomenon heterosis represents the…

Historically, interesting psychological theories have been phrased in terms of correlation coefficients, which are standardized covariances, and various statistics derived from them. Methodological practice over the last 40 years, however, has suggested it is necessary to transform such theories into hypotheses on covariances and statistics…

A picture of a 95% confidence interval (CI) implicitly contains pictures of CIs of all other levels of confidence, and information about the "p"-value for testing a null hypothesis. This article discusses pictures, taken from interactive software, that suggest several ways to think about the level of confidence of a CI,…

A method for estimating criterion validity of scales with homogeneous components is outlined. It accomplishes point and interval estimation of interrelationship indices between composite scores and criterion variables and is useful for testing hypotheses about criterion validity of measurement instruments. The method can also be used with missing…

Prior research has established that the depth and breadth of remedial need in basic skills (math and English) exhibited by a student at college entry are strongly and negatively associated with the likelihood of achieving college-level competency in those subjects (i.e., successful remediation). This well-documented finding is built upon a body of…