Lívia Dorneles Audino <livia.audino <at> gmail.com> writes: > > I'm trying to make a glmm to identify the relationship between insect > species richness with fragment size, isolation and time (different years). > I already tried to analyse it using poisson distribution error, but I > always face with the following warning: > *glm.fit: fitted probabilities numerically 0 or 1 occurred * > > This is probably hapenning because my dataset has a lot of zeros. So, what > error distribution should I use? >
I know you haven't gotten a lot of help on r-sig-mixed-models (sorry), but it would probably be better to post this question there. The answer is that this is a warning, not an error, so it indicates a need for caution but not necessarily that anything is wrong. In this case, an internal call to glm.fit() has difficulty when it tries to fit a subset of that data that are all-zero or all-one. It's quite possibly OK, provided that you've looked at your results, plotted predicted values, etc., and everything seems to make sense. ______________________________________________ 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.
