That is exactly how I am writing it. Glm works fine, but as I stated the residual deviance is much greater (10x) than the degrees of freedom. I want to take a look at using the negative binomial distribution, but I can't get glm.nb to work. I get the message Error: (subscript) logical subscript too long. I have used traceback() and it seems to be in the glm.fitter function, but as I say I am at the limit of my abilities here.
Wade On Thu, Apr 3, 2008 at 7:23 AM, Michael Dewey <[EMAIL PROTECTED]> wrote: > At 17:03 02/04/2008, Wade Wall wrote: > > > Hi all, > > > > I have count data (number of flowering individuals plus total number of > > individuals) across 24 sites and 3 treatments (time since last burn). > > Following recommendations in the R Book, I used a glm with the model y~ > > burn, with y being two columns (flowering, not flowering) and burn the > > time > > (category) since burn. However, the residual deviance is roughly 10 > > times > > the number of degrees of freedom, and using the quasibinomial > > distribution > > doesn't change this. Any suggestions as to why the quasibinomial > > distribution doesn't change the residual deviance and how I should > > proceed. > > I know that this level of residual deviance is unacceptable, but not > > sure is > > transformations are in order. > > > > You have received much helpful advice from Gavin and Achim and others but > I wonder whether they are answering the quaestion in your title rather than > in your post. > > Are you doing something like > fit <- glm(cbind(flower, notflower) ~ burn, family = binomial) > > You might find it helpful to read the relevant section in MASS (see > quasibinomial in the index) or in some other text. > > > Needless to say that I am at the outer limits of my statistical > > knowledge. > > > > Thanks for any help, > > > > Wade Wall > > > > [[alternative HTML version deleted]] > > > > Michael Dewey > http://www.aghmed.fsnet.co.uk > > [[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.
