[R] calculating dispersion formula using deviance ( was Re: (no subject) )

From: Adaikalavan Ramasamy <ramasamy_at_cancer.org.uk>
Date: Mon 11 Jul 2005 - 20:19:16 EST

Please try to use a meaningful subject line. See below for comments.

On Mon, 2005-07-11 at 11:30 +0200, Smit, R. (Robin) wrote:
> Hello,
>
> The estimate of glm dispersion can be based on the deviance or on the
> Pearson statistic.
> I have compared output from R glm() to another statastical package and
> it appears that R uses the Pearson statistic.

A quick search would also highlight the following thread http://www.r-project.org/nocvs/mail/r-help/2002/6938.html

> I was wondering if it is possible to make use R the deviance instead by
> modifying the glm(...) function?

I don't know what the formula for using the deviance is but _IF_ it is the square root of ratio of null deviance by its degrees of freedom, then sqrt( fit$deviance / fit$df.null ) should be useful.

> Thanks for your attention.
>
> Kind regards,
> Robin Smit
>
>
>
> This e-mail and its contents are subject to the DISCLAIMER at http://www.tno.nl/disclaimer/email.html
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>



R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Mon Jul 11 20:56:53 2005

This archive was generated by hypermail 2.1.8 : Fri 03 Mar 2006 - 03:33:28 EST