The article illustrates a method to estimate changes in the statistical power of a study which are caused by changes in the reliability of the dependent variable. (Author)

A general analysis strategy is proposed such that the universe of inference is increased incrementally. The strategy prevents logically incongruent findings that occasionally result when the conventional analysis strategy is employed. (Author)

The recommendation to use group means when there may be nonindependence among observational units is unduly restrictive. When random factors are properly identified and included in the analysis, the results are identical in balanced analysis of variance designs, irrespective of whether group means or individual observations are employed.…

A metanalysis involving 62 studies compared the response rate to mailed surveys with and without a monetary gratuity. The average response rate increased 19% when a gratuity was enclosed. Other findings that substantiate that the external validity of surveys can be increased by gratuities are discussed. (SLD)

The purpose of this training workbook is to provide the user with an understanding of Analysis of Covariance (ANCOVA) sufficient to allow him to identify situations in which it can increase the credibility and the statistical power of the analysis. The module provides a conceptual, nonmathematical overview of the purposes of ANCOVA. The…

Quick power estimates for detecting a difference in two population proportions are expedient during early stages of research planning. Such estimates are tabled and graphed in this article. They are shown to be conservative but accurate for most research situations when proportions fall in the range of 0.25 to 0.75. (SLD)

The purpose of this module is to provide the researcher and the consumers of such research with a recognition of the assumptions and appropriate use and interpretation of each of 10 multiple comparison (MC) statistical techniques. In this self-contained and self-instructional module, the user is sensitized to the serious consequences of…

In behavior research using cognitive and affective measures, there is often incongruity between the statistical analysis employed and the intended inference. This paper argues that incorporating items as levels of a random facet via generalizability theory allows the statistical examination of the inferential question in the desired universe of…

This self-contained and self-instructional unit is intended for use by evaluation and development personnel and by students in introductory research and evaluation courses. The unit contains a discussion of the regression employing graphic illustrations with actual data. The user is introduced to the regression effect in the single group…