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Testing for equivalence of group variances

Testing for equivalence of group variances

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Title: Testing for equivalence of group variances
Author: Mara, Constance A.
Abstract: "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. "
Type: Electronic Thesis or Dissertation
Rights: Author owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.
URI: http://hdl.handle.net/10315/32511

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