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2005 Oct 07
1
The mathematics inside lme()
Hello all! Consider a dataset with a grouping structure, Group (factor) Several treatments, Treat (factor) Some sort of yield, Yield (numeric) Something, possibly important, measured for each group; GroupCov (numeric) To look for fixed effects from Treat on Yield, a first attempt could be: m1 <- lm(Yield ~ Treat) which gives, in a symmetric situation, the same estimated fixed effects as: m2 <- lme(Yield ~ Treat, random =~1| Group) but m2 is a much better model with safer significan...