Message-ID: <28250202.18844.1295879910549.JavaMail.nabble@joe.nabble.com>
Date: 2011-01-24T14:38:30Z
From: Francesco Nutini
Subject: lm() and post hoc test
Dear Alex,
I have read your question about post-hoc test:
"Let's assume that according to Anova(lm(y~a*b, data=d)) the a:b interaction is significant, and I would like to know if there are specific combinations of a and b levels that differ from the control group. Are there any caveats against simply looking at the p-values in the output generated by summary(lm(y~a*b,data=d))? The documentation for summary.lm says nothing about multiple comparison correction, so I assume I need to do that myself, is that correct?"
I have the same problem about the interpretation of command "summary", and generically about the finest post-hoc test for implemented model with the code "lm()". I think that R-help is quite insufficient...
Which command did you use normally?
Thanks a lot,
Francesco Nutini