María J Blanca, Jaume Arnau, F J García-Castro, Rafael Alarcón, Roser Bono
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引用次数: 12
Abstract
Background: Repeated measures designs are commonly used in health and social sciences research. Although there are other, more advanced, statistical analyses, the F-statistic of repeated measures analysis of variance (RM-ANOVA) remains the most widely used procedure for analyzing differences in means. The impact of the violation of normality has been extensively studied for between-subjects ANOVA, but this is not the case for RM-ANOVA. Therefore, studies that extensively and systematically analyze the robustness of RM-ANOVA under the violation of normality are needed. This paper reports the results of two simulation studies aimed at analyzing the Type I error and power of RM-ANOVA when the normality assumption is violated but sphericity is fulfilled.
Method: Study 1 considered 20 distributions, both known and unknown, and we manipulated the number of repeated measures (3, 4, 6, and 8) and sample size (from 10 to 300). Study 2 involved unequal distributions in each repeated measure. The distributions analyzed represent slight, moderate, and severe deviation from normality.
Results: Overall, the results show that the Type I error and power of the F-statistic are not altered by the violation of normality.
Conclusions: RM-ANOVA is generally robust to non-normality when the sphericity assumption is met.
期刊介绍:
La revista Psicothema fue fundada en Asturias en 1989 y está editada conjuntamente por la Facultad y el Departamento de Psicología de la Universidad de Oviedo y el Colegio Oficial de Psicólogos del Principado de Asturias. Publica cuatro números al año. Se admiten trabajos tanto de investigación básica como aplicada, pertenecientes a cualquier ámbito de la Psicología, que previamente a su publicación son evaluados anónimamente por revisores externos. Psicothema está incluida en las bases de datos nacionales e internacionales más relevantes, entre las que cabe destacar Psychological Abstracts, Current Contents y MEDLINE/Index Medicus, entre otras. Además, figura en las listas de Factor de Impacto del Journal Citation Reports. Psicothema es una revista abierta a cualquier enfoque u orientación psicológica que venga avalada por la fuerza de los datos y los argumentos, y en la que encuentran acomodo todos los autores que sean capaces de convencer a los revisores de que sus manuscritos tienen la calidad para ser publicados. Psicothema es una revista de acceso abierto lo que significa que todo el contenido está a disposición de cualquier usuario o institución sin cargo alguno. Los usuarios pueden leer, descargar, copiar, distribuir, imprimir, buscar, o realizar enlaces a los textos completos de esta revista sin pedir permiso previo al editor o al autor, siempre y cuando la fuente original sea referenciada. Para acervos y repositorios, se prefiere que la cobertura se realice mediante enlaces a la propia web de Psicothema. Nos parece que una apuesta decidida por la calidad es el mejor modo de servir a nuestros lectores, cuyas sugerencias siempre serán bienvenidas.