Hi Steve: On Fri, Feb 5, 2010 at 10:10 AM, <steve_fried...@nps.gov> wrote:
> > Hi everyone, > > I am trying to construct a glm and am running into a couple of questions. > > The data set I am using consists of 6 categories for the response and 6 > independent predictors representing nutrient concentrations at sample point > locations. Ultimately I'd like to use the probabilities for each response > category in a simulation model such that these probabilities are used to > define a realized ecological niche. > Isn't this a multinomial logistic regression model? I don't think this will work with glm(). I'd look into the rms package of Frank Harrell's group (function lrm), the VGAM package and the mlogit package for what I think are more appropriate alternatives. If the response is unordered, then multinomial() in the nnet package is another alternative. Laura Thompson has been maintaining a book-length project showing how to use R/S-PLUS to do the exercises in Agresti's Categorical Data Analysis book. The latest version is here: https://home.comcast.net/~lthompson221/Splusdiscrete2.pdf Chapter 7 is on multinomial logit models (unordered and ordered). HTH, Dennis [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
