Message-ID: <5.0.2.1.0.20030408114333.00ab7c20@cres.anu.edu.au>
Date: 2003-04-08T02:00:04Z
From: Joern Fischer
Subject: truncated poisson in glm / glmmPQL
Hi
I'm a postgrad in ecology, and have recently started to use R. I'm planning
to model various sets of animal abundance (i.e. count) data in relation to
habitat data using glm's and/or glmmPQL's. However, some of my potential
response variables have many zeros. From what I gather the "family = ..."
option in the command line does not allow for the direct specification of a
truncated / zero-modified poisson distribution. My problem is probably not
uncommon, but I could not find anything on truncated poisson distributions
in the R web pages or documentation.
Does anyone know of a bit of software that someone may have written to deal
with this problem? I'm interested in modifications to the poisson as well
as quasipoisson families.
Thanks a lot for your help - Joern.