[R] Wrong contrast matrix for nested factors in lm(), rlm(), and lmRob()

Rob.fit.compute() cannot be made to work? R%%>sessionInfo() R version 2.12.0 (2010-10-15) Platform: x86_64-redhat-linux-gnu (64-bit) ---- I'll be very grateful for any help. Saul

[R] model.matrix() and lm() for nested factors

uot;by hand" and provide them as arguments to lim.fit() and lmRob.fit.compute()? (3) If one uses lm.fit() and lmRob.fit.compute() directly in this way, then, given that one is warned against doing so, what are the dangers? Many thanks. Sau