R help - Jan 2011 - Anova with repeated measures for unbalanced design

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)


Does the same code still work for unbalanced design?
Can anyone provide a R example of code in order to get the same analysis?


Thanks in advance for any suggestion.

Best regards


      
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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.