swertie <v_coudrain <at> voila.fr> writes: > I am trying to model data on species abundance (count data) with a poisson > error distribution. I have a fixed and a random variables and thus needs a > mixed model. I strongly doubt that my model is overdispersed but I don't > know how to get the overdispersion parameter in a mixed model. Maybe someone > can help me on this point. Secondly, it seems that quasi models cannot be > implemented with the function lmer, is there an option? If not, I certainly > should go to variable transformation and use a gaussian error distribution, > but it is not optimal.
You should read the section in http://glmm.wikidot.com/faq on overdispersion, and address further questions to the r-sig-mixed-models <at> r-project.org mailing list ... Ben Bolker ______________________________________________ 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.
