[R] repeated measures help; disagreement with SPSS

[Peter Dalgaard BSA]

Greg Trafton <trafton at itd.nrl.navy.mil> writes:

> > summary(aov(rl ~ cond * session + Error(subj/(session)), data=mig))
> 
> Error: subj
>           Df Sum Sq Mean Sq F value Pr(>F)
> cond       2 28.305  14.153  1.9916 0.2311
> Residuals  5 35.531   7.106               
> 
> Error: subj:session
>              Df  Sum Sq Mean Sq F value  Pr(>F)  
> session       2  4.4502  2.2251  2.9868 0.09616 .
> cond:session  4 17.7335  4.4334  5.9509 0.01024 *
> Residuals    10  7.4499  0.7450                  
> ---
> Signif. codes:  0  `***'  0.001  `**'  0.01  `*'  0.05  `.'  0.1  ` '  1 
> 
> (I ran this one this way b/c of a similar example from Baron's "Notes
> for psychology experiments.  Unfortunately, neither the session nor
> the interaction cond:session are the same as SPSS's output, though the
> degrees of freedom are correct in both, of course).
> 
> I'm certainly able to believe that SPSS is wrong and R is right, but
> thought I'd check with this list to make sure I'm not doing something
> completely stupid...

This is consistent with both lm() (using subj as a systematic effect)
and lme(), so I'd strongly suspect that SPSS is getting it wrong. What
does SPSS give?

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._