Online Program
| Thursday, February 19 | |
| PS1 Poster Session 1 & Opening Mixer |
Thu, Feb 19, 5:30 PM - 7:00 PM
Napoleon AB |
Testing Homogeneity of Variance in One-Factor ANOVA Models: A Plethora of Approaches to Consider (303006)Aarti Bellara, University of South FloridaYi-hsin Chen, University of South Florida Tyler Hicks, University of South Florida Harold Holmes, University of South Florida Eun Sook Kim, University of South Florida *Jeffrey D. Kromrey, University of South Florida Isaac Li, University of South Florida Sean Murphy, University of South Florida Diep T. Nguyen, University of South Florida Thanh Pham , University of South Florida Patricia Rodríguez de Gil, University of South Florida Jeanine Romano, University of South Florida Yan Wang, University of South Florida Keywords: Homogeneity of variance, Analysis of variance, Non-normality, Type I error control, Statistical power The validity of the results of an ANOVA test is largely dependent on satisfying the homogeneity of variance, normality, and independence assumptions. Violations of these assumptions lead to distorted type I error rates. A variety of tests to check the homogeneity of variances assumption have been proposed in the literature, yet there is no consensus as to which test is most appropriate. A simulation study was conducted to explore the type I error rates and statistical power of 14 approaches for testing the homogeneity of variance assumption in one-way ANOVA models. Seven factors were manipulated in the study: number of groups, average number of observations per group, pattern of sample sizes in groups, pattern of population variances, maximum variance ratio, population distribution shape, and nominal alpha level for the test of variances. Results from this study delineate the performance of the tests under a wide variety of conditions, providing researchers with information to guide the selection of a valid test for assessing the tenability of this critical assumption. In addition, a SAS macro is provided to offer a simple vehicle to conduct these tests.
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