"David Barron" <mothsailor at googlemail.com> writes:
I'm not sure if this will help, but it's worth a try. Do the regression as I suggested before, extract the model matrix and remove the "offending" column. I'm assuming you don't know in advance how many levels there are in the factor. Then use this to perform the regression. Something like this: m1 <- lm(x ~ fd:y + fd) mm <- model.matrix(m1) nl <- length(levels(fd)) newdat <- mm[,-c(1,nl)] lm(x ~ newdat)
Thanks a lot! With a small change that solved my problem!
Andreas G?sele Omnis enim res, quae dando non deficit, Inst. f. Gesellschaftspolitik dum habetur et non datur, Kaulbachstr. 31a, 80539 M?nchen nondum habetur, quomodo habenda est. E-mail: goesele at hfph.mwn.de (Augustinus)