[R] ANCOVA with defined error terms
Richard M. Heiberger
rmh at temple.edu
Thu Aug 20 05:21:57 CEST 2009
track.aov <- aov(mice ~ coon
+ block*veget*fruit*time - block:veget:fruit:time
+ Error(block/plot), data = track)
I think this is what you are looking for. This model in words says,
What is the effect of the four-way crossing after adjusting for
the covariate coon? We don't have enough degrees of freedom for
the full crossing, so remove the four-way interaction.
anova() gives the sequential sums of squares of (multi-degree of
freedom) effects. Be sure that the five variables (block, veget, fruit,
time, plot) are factors. I am assuming time is a factor here.
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