[R] Anova with repeated measures for unbalanced design
Ben Bolker
bbolker at gmail.com
Sat Jan 8 21:39:20 CET 2011
Frodo Jedi <frodo.jedi <at> yahoo.com> writes:
>
> Dear all,
> I need an help because I am really not able to find over
> internet a good example
> in R to analyze an unbalanced table with Anova with
> repeated measures.
> For unbalanced table I mean that the questions are
> not answered all by the same
> number of subjects.
>
> For a balanced case I would use the command
>
> aov1 = aov(response ~ stimulus*condition +
> Error(subject/(stimulus*condition)),
> data=scrd)
I recommend that you find a copy of Pinheiro and Bates 2000 ...
>
> Does the same code still work for unbalanced design?
No, it doesn't.
> Can anyone provide a R example of code in order to get the same analysis?
Something like
library(nlme)
lme1 <- lme(response~stimulus*condition,random=~1|subject,data=scrd)
or possibly
lme1 <- lme(response~stimulus*condition,random=~stimulus*condition|subject,
data=scrd)
if your experimental design would allow you to estimate stimulus and condition
effects for each subject.
Further questions along these lines should probably go to
the r-sig-mixed-model mailing list.
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