Blanca Mena, M. JoséAlarcón Postigo, RafaelArnau Gras, JaumeGarcía Castro, JavierBono Cabré, Roser2025-02-182025-02-182024-100212-9728https://hdl.handle.net/2445/218943Adjusted F-tests have typically been proposed as an alternative to the F-statistic in repeated measures ANOVA. Despite considerable research, it remains unclear how these statistics perform under simultaneous violation of normality and sphericity. Accordingly, our aim here was to conduct a detailed examination of Type I error and power of the F-statistic and the Greenhouse-Geisser (F-GG) and Huynh-Feldt (F-HF) adjustments, manipulating the number of repeated measures (3-6), sample size (10-300), sphericity (epsilon estimator of Greenhouse-Geisser from its lower to upper limit), and distribution shape (slight to extreme deviations from normality). The findings show that the behavior of F-GG and F-HF depends on the degree of violation of both normality, sphericity, and sample size. Overall, we suggest using F-GG under violation of sphericity and slight or moderate deviations from normality in all sample size; with severe deviations from both normality and sphericity F-GG may be used with a sample size larger than 10; and with extreme deviation from both normality and sphericity this statistic may be used with a sample size larger than 30. In the event of discrepant results between F-GG and F-HF, the choice depends on the epsilon value.15 p.application/pdfengcc-by-nc-nd (c) Universidad de Murcia, 2024http://creativecommons.org/licenses/by-nc-nd/4.0/Anàlisi de variànciaCiències socialsModels lineals (Estadística)Analysis of varianceSocial sciencesLinear models (Statistics)info:eu-repo/semantics/article7414182025-02-18info:eu-repo/semantics/openAccess