Hi Roman, thanks for your response. I admit I was thinking of the 'dredging' type at this stage. In this particular case, it probably won't make much difference as my data doesn't show much in the way of patterns. I am going through the model selection process to test for effects of treatment, plant density and the interaction
cheers, James On Tue, Jan 6, 2015 at 2:00 PM, Roman Luštrik <[email protected]> wrote: > What kind of model selection are we talking about? The dredging part (a la > step()) or a more fine tuned, such as information-theoretic approach > advocated by (among others) Burnham and Anderson? > > I would suggest the latter. Pardon me if I'm presuming too much, but in a > nutshell, this approach advocates formulating a set of plausible > hypotheses, constructing models to reflect them, and then compare based on > some criterion (like AIC). You can also use model averaging (using weights) > to get a better sense of model estimates. > > Cheers, > Roman > > On Tue, Jan 6, 2015 at 12:52 PM, James Rodger <[email protected]> wrote: > >> Hi, >> >> Can anyone advise me on model selection in glm with a zero truncated >> poisson distribution? >> >> I have used a the command vglm in the vgam package to analyse the data >> with >> pospoisson specified as the family and I have evaluated alternative models >> with a log-likelihood test. I am not sure if that the test statistic will >> follow the chi-squared distribution, however. >> >> My data is on seeds per fruit (minimum 1) in different experimental >> treatments and different densities of plants. >> >> Regards, >> >> James >> >> [[alternative HTML version deleted]] >> >> _______________________________________________ >> R-sig-ecology mailing list >> [email protected] >> https://stat.ethz.ch/mailman/listinfo/r-sig-ecology >> > > > > -- > In God we trust, all others bring data. > [[alternative HTML version deleted]] _______________________________________________ R-sig-ecology mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
