Hi Spencer,
Em Dom 04 Set 2005 20:31, Spencer Graves escreveu:
Others may know the answer to your question, but I don't. However,
since I have not seen a reply, I will offer a few comments:
1. What version of R are you using? I just tried superficially
similar things with the examples in ?aov in R 2.1.1 patched and
consistently got F and p values.
I'm using the R version 2.1.1 on Linux Debian
Version 2.1.1 (2005-06-20), ISBN 3-900051-07-0
2. My preference for this kind of thing is to use lme in
library(nlme) or lmer in library(lme4). Also, I highly recommend
Pinheiro and Bates (2000) Mixed-Effects Models in S and S-Plus (Springer).
Yes, this is my preference too, but I need aov for classes.
3. If still want to use aov and are getting this problem in R 2.1.1,
could you please provide this list with a small, self contained example
that displays the symptoms that concern you? And PLEASE do read the
posting guide! "http://www.R-project.org/posting-guide.html". It might
increase the speed and utility of replies.
spencer graves
I send the complete example. This is a example from the Crwaley's book
(Statistical Computing: An introdution to data analysis using S-Plus.
This is a classical experiment to show pseudoreplication, from Sokal and Rohlf
(1995).
In this experiments, It have 3 treatmens applied to 6 rats, for each rat it
make 3 liver preparation and for each liver it make 2 readings of glycogen.
This generated 6 pseudoreplication per rat. I'm interested on the effect os
treatment on the glycogen readings.
Look the R analyses:
--------------------
### Model made identical to the book
model <- aov(Glycogen~Treatment/Rat/Liver+Error(Treatment/Rat/Liver))
summary(model)
Error: Treatment
Df Sum Sq Mean Sq
Treatment 2 1557.56 778.78
Error: Treatment:Rat
Df Sum Sq Mean Sq
Treatment:Rat 3 797.67 265.89
Error: Treatment:Rat:Liver
Df Sum Sq Mean Sq
Treatment:Rat:Liver 12 594.0 49.5
Error: Within
Df Sum Sq Mean Sq F value Pr(>F)
Residuals 18 381.00 21.17
### Model made by myself, I'm interested only in Treatment effects
model <- aov(Glycogen~Treatment+Error(Treatment/Rat/Liver))
summary(model)
Error: Treatment
Df Sum Sq Mean Sq
Treatment 2 1557.56 778.78
Error: Treatment:Rat
Df Sum Sq Mean Sq F value Pr(>F)
Residuals 3 797.67 265.89
Error: Treatment:Rat:Liver
Df Sum Sq Mean Sq F value Pr(>F)
Residuals 12 594.0 49.5
Error: Within
Df Sum Sq Mean Sq F value Pr(>F)
Residuals 18 381.00 21.17
--------------------
What it dont calculate the F and P for treatment?
Thanks
Ronaldo