Re: [R] glht() and contrast() comparison

2008-01-11 Thread Gang Chen
With the example you provided, it seems both glht() and contrast() work fine. Based on my limited experience with contrast(), if you encounter such an error message you just mentioned, check > dat.lme$apVar You might see something like this [1] "Non-positive definite approximate variance

[R] glht() and contrast() comparison

2008-01-11 Thread array chip
Hi, I have been trying glht() from multcomp package and contrast() from contrast package to test a contrast that I am interested in. With the following simulated dataset (fixed effect "type" with 3 levels (b, m, t), and random effect "batch" of 4 levels, a randomized block design with interaction