[R] Post-hoc t-tests in 2-way repeated measure ANOVA

Giuseppe Pagnoni gpagnon at emory.edu
Thu Aug 5 16:51:22 CEST 2004

Hi all

I am running a 2-way repeated measure anova with 1 between-subjects 
factor (Group=treatment, control), and 1 within-subject factor (Time of 
measurement: time1, time2).  I extract the results of the anova with:

summary(aov(effect ~ Group*Time + Error=Subj/Time, data=mydata))

Now, this must be clearly a dumb question, but how can I quickly extract 
in R all the post-hoc t-tests for the simple main effects?

Also, while I am at it, how do I enter in the model a counfounding 
covariate (e.g., Age)?

And on a different matter, is there a way to receive interactive user 
input in an R script? Something like "Enter the name of  the factor:  ", 
or even more simply "Press <Enter> to see the result of the next 

thanks in advance for any suggestions!


Giuseppe Pagnoni, Ph.D.
Dept. of Psychiatry and Behavioral Sciences
1639 Pierce Drive, Suite 4000
WMB Bldg., Atlanta, GA 30322, U.S.
phone: 404-712-8431
fax: 404-727-3233
e-mail: gpagnon at emory.edu

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