Cribbie, RobertFlora, DavidLalonde, Richard2016-10-292016-10-292013-06http://hdl.handle.net/10315/32511"The purpose of this paper was to situate a test for equality of group variances within the equivalence testing framework. Even though difference-based procedures are appropriate to answer questions about differences in some statistic (e.g., means, variances, etc.), these procedures are not appropriate to address questions related to variance homogeneity. Thus, if a researcher is interested in evaluating the similarity of group variances, it is more appropriate to use a procedure specifically designed to determine equivalence. A simulation study was used to compare newly developed equivalence-based tests to currently recommended difference-based variance homogeneity tests under data conditions common in psychological research. The results of this study provided evidence regarding the problems with assessing equality of variances with traditional difference-based tests. Most notably, traditional difference-based tests assess equality of variances from the wrong perspective, encouraging researchers to ""accept"" the null hypothesis. The results also demonstrated that the newly developed Levene-Wellek- Welch test for equivalence of group variances using the absolute deviations from the median was the best-performing equivalence-based test statistic in terms of accurate Type I error rates and highest power for detecting equivalence across the conditions evaluated. In addition, the use of the Levene-Wellek-Welch median-based test was demonstrated with an applied example, and an R function was provided in order to facilitate use of this newly developed equivalence of group variances test. "Author owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.Electronic Thesis or DissertationEquivalenceGroup variancesDifference-based proceduresLevene-Wellek-Welch test