Hello,
I am trying to make the switch from SAS, and I have a fairly elemental problem with syntax using the nlme package for analyzing mixed models. There was a previous question on this topic posted to this list, so I apologize for redundancy, but I didn't understand the advice given to that inquiry. The model I want to run has the following factors: Host (fixed) Sire (random) Dam nested within Sire (random) Host * Sire (random) Host * Dam within Sire (random) So without the interactions I have: hogmodel = lme(gain ~ host, random = ~1|sire/dam) If I understand correctly, that "sire/dam" term gives me both Sire and Dam within Sire as random factors. OK, so now I want to add the two interactions (listed above)... In SAS, I would just enter them as random factors, but I can't seem to make that work. I think I need to make a list that includes Sire/Dam, Host:Sire, and Host:Sire/Dam. Two questions: 1) Is it sufficient to have simply Host:Sire/Dam in order to code for both interactions (host*sire and host*dam-within-sire)? 2) In any event, WHAT IS THE SYNTAX FOR MAKING A LIST OF RANDOM FACTORS? I have looked in section 1.3 of Pinheiro&Bates, which was helpful, but I wasn't able to answer my question. Thanks in advance, your help will keep me from running back to SAS! --Matt - - - Matthew L Forister Department of Ecology and Evolution State University of New York at Stony Brook 650 Life Sciences Building Stony Brook, New York 11794-5245 Email: [EMAIL PROTECTED] Webpage: http://life.bio.sunysb.edu/~forister/ Lab phone: (631) 632-8609 Fax: (631) 632-7626 - - - ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
