[R] glm() for log link and Weibull family

From: Robert A. LaBudde <ral_at_lcfltd.com>
Date: Fri, 08 Jun 2007 14:18:34 -0400


I need to be able to run a generalized linear model with a log() link and a Weibull family, or something similar to deal with an extreme value distribution.

I actually have a large dataset where this is apparently necessary. It has to do with recovery of forensic samples from surfaces, where as much powder as possible is collected. This apparently causes the results to conform to some type of extreme value distribution, so Weibull is a reasonable starting point for exploration.

I have tried ('surface' and 'team' are factors)

glm(surfcount ~ surface*team, data=powderd, family=Gamma(link='log'))

but this doesn't quite do the trick. The standardized deviance residuals are still curved away from normal at the tails.

Thanks for any info you can give on this nonstandard model.



Robert A. LaBudde, PhD, PAS, Dpl. ACAFS e-mail: ral_at_lcfltd.com
Least Cost Formulations, Ltd.            URL: http://lcfltd.com/
824 Timberlake Drive                     Tel: 757-467-0954
Virginia Beach, VA 23464-3239            Fax: 757-467-2947

"Vere scire est per causas scire"



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