[R] power analysis for 2-way anova interaction

Justin Rhodes jrhodes at cyrus.psych.uiuc.edu
Thu Apr 13 16:51:47 CEST 2006

Dear R-help,

Does anyone have a function that I could use to determine power for 
testing significance of an interaction term in a 2-way ANOVA.  The 
model I am considering has 2 levels in each factor.  I would like to 
be able to input sample size (equal in all groups), MSE, means for 
the 4 groups, and then get power for the 2 main effects and 
interaction term.  It would also be nice to enter the desired power 
for the interaction effect, and then get sample size for the 4 
groups.  Any help or guidance would be greatly appreciated.

Best wishes,

Justin S. Rhodes
Department of Psychology
Beckman Institute
Neuroscience Program, Institute for Genomic Biology
University of Illinois
405 N. Mathews Avenue
Urbana, IL 61801

Ph: 217-265-0021
Fax: 217-244-5180
e-mail: jrhodes at uiuc.edu

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