AOV with repeated measures

You probably need specify the repeated measures by using an "Error" term in aov for repeated measures:

aov(trait ~ species + strain + Error(species/strain))

Take a look at Ripley's book.

Treat above with caution: I am no expert, but the answer is in that direction...

Michael Jerosch-Herold



I have a question on using R to analyze data with repeated measurements. I 
have 2 species with several strains (12) per species, each of which has 
been measured twice with for a given trait. No particular covariance, just 
two measures. Now I want to analyze the data with an ANOVA (aov) 
considering these repeated measures to get the MSq and SSq for the species 
and strain level. I would like to know how to write the ANOVA model in R. I 
have done the following:

aov(trait ~ species + strain/replicate)

Is it accurate?

Thanks a lot,

Christian