Message-ID: <E415F473-DCB4-4E3B-B50C-ABDB09C7E20F@MUOhio.edu>
Date: 2005-10-10T19:57:09Z
From: Martin Henry H. Stevens
Subject: Under-dispersion - a stats question?
Hello all:
I frequently have glm models in which the residual variance is much
lower than the residual degrees of freedom (e.g. Res.Dev=30.5, Res.DF
= 82). Is it appropriate for me to use a quasipoisson error
distribution and test it with an F distribution? It seems to me that
I could stand to gain a much-reduced standard error if I let the
procedure estimate my dispersion factor (which is what I assume the
quasi- distributions do).
Thank you for any input at all.
Hank
Dr. Martin Henry H. Stevens, Assistant Professor
338 Pearson Hall
Botany Department
Miami University
Oxford, OH 45056
Office: (513) 529-4206
Lab: (513) 529-4262
FAX: (513) 529-4243
http://www.cas.muohio.edu/~stevenmh/
http://www.muohio.edu/ecology/
http://www.muohio.edu/botany/
"E Pluribus Unum"