> treat_code is a dummy > variable, but that shouldn't matter. Any suggestions?
It does matter to TukeyHSD. If treat_code is a numeric variable with discrete values 0 and 1, then it does not have class "factor". It is true that aov will give the same ANOVA table for a two-level factor as for a two-value numeric. It will give different ANOVA tables if there are more than two values. TukeyHSD will refuse to do anything for a numeric variable. It insists on factors. You must use the statement mydata$treat_code <- factor(mydata$treat_code) before creating the aov object that you give to TukeyHSD. Rich ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
