naa a22 4500 510776833 CHVBK 20180411083233.0 cr unu---uuuuu 180411e20130901xx s 000 0 eng 10.3758/s13428-012-0306-x doi (NATIONALLICENCE)springer-10.3758/s13428-012-0306-x The effect of skewness and kurtosis on the robustness of linear mixed models [Elektronische Daten] [Jaume Arnau, Rebecca Bendayan, María Blanca, Roser Bono] This study analyzes the robustness of the linear mixed model (LMM) with the Kenward-Roger (KR) procedure to violations of normality and sphericity when used in split-plot designs with small sample sizes. Specifically, it explores the independent effect of skewness and kurtosis on KR robustness for the values of skewness and kurtosis coefficients that are most frequently found in psychological and educational research data. To this end, a Monte Carlo simulation study was designed, considering a split-plot design with three levels of the between-subjects grouping factor and four levels of the within-subjects factor. Robustness is assessed in terms of the probability of type I error. The results showed that (1) the robustness of the KR procedure does not differ as a function of the violation or satisfaction of the sphericity assumption when small samples are used; (2) the LMM with KR can be a good option for analyzing total sample sizes of 45 or larger when their distributions are normal, slightly or moderately skewed, and with different degrees of kurtosis violation; (3) the effect of skewness on the robustness of the LMM with KR is greater than the corresponding effect of kurtosis for common values; and (4) when data are not normal and the total sample size is 30, the procedure is not robust. Alternative analyses should be performed when the total sample size is 30. Psychonomic Society, Inc., 2013 Linear mixed model nationallicence Kenward-Roger procedure nationallicence Skewness nationallicence Kurtosis nationallicence Robustness nationallicence Arnau Jaume Department of Methodology of the Behavioral Sciences, University of Barcelona, Barcelona, Spain aut Bendayan Rebecca Department of Psychobiology and Methodology of Behavioural Sciences, University of Málaga, Málaga, Spain aut Blanca María Department of Psychobiology and Methodology of Behavioural Sciences, University of Málaga, Málaga, Spain aut Bono Roser Department of Methodology of the Behavioral Sciences, University of Barcelona, Barcelona, Spain aut Behavior Research Methods Springer US; http://www.springer-ny.com 45/3(2013-09-01), 873-879 45:3<873 2013 45 13428 https://doi.org/10.3758/s13428-012-0306-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.3758/s13428-012-0306-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Arnau Jaume Department of Methodology of the Behavioral Sciences, University of Barcelona, Barcelona, Spain aut NATIONALLICENCE 700 1- Bendayan Rebecca Department of Psychobiology and Methodology of Behavioural Sciences, University of Málaga, Málaga, Spain aut NATIONALLICENCE 700 1- Blanca María Department of Psychobiology and Methodology of Behavioural Sciences, University of Málaga, Málaga, Spain aut NATIONALLICENCE 700 1- Bono Roser Department of Methodology of the Behavioral Sciences, University of Barcelona, Barcelona, Spain aut NATIONALLICENCE 773 0- Behavior Research Methods Springer US; http://www.springer-ny.com 45/3(2013-09-01), 873-879 45:3<873 2013 45 13428 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer