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Re: overdispersion in logistic regression

To: Tim Hesterberg <timh@insightful.com>
Subject: Re: overdispersion in logistic regression
From: Spencer Graves <spencer.graves@pdf.com>
Date: Thu, 14 Jul 2005 10:30:32 -0700
Cc: mtexeira@agro.uba.ar, s-news@lists.biostat.wustl.edu
In-reply-to: <SE2KEXCH01XaD8z9tTx00002d96@se2kexch01.insightful.com>
References: <1121105272.42d2b5783d0a6@webmail3.agro.uba.ar> <SE2KEXCH01XaD8z9tTx00002d96@se2kexch01.insightful.com>
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Have you tried "family=quasi"? See "?glm", "?family", "?anova.glm", and "args(anova.glm)". In particular, you want 'test="Chisq"' or even 'test="F"'.

          spencer graves

Tim Hesterberg wrote:

Everybody knows how can I correct for overdispersion in a logistic regression problem ?

thanks
Marcos Texeira


I would typically estimate parameters ignoring the over-dispersion,
then specified the dispersion when calling summary().
I don't recall if I estimated the dispersion myself, or passed
dispersion = 0.
See help(summary.glm)

Tim Hesterberg

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