Re: [R] testing factor effects in glm

From: Thomas Lumley <tlumley_at_u.washington.edu>
Date: Thu 23 Feb 2006 - 02:48:09 EST

On Wed, 22 Feb 2006, I.Szentirmai wrote:

> Dear All,
>
> I'm using a glm to analyse the effect of year on a
> variable with poisson distribution. Using the summary() I
> can test whether years are different from each other, but
> how can I test whether year has an overall effect on my
> respons variable? My guess is that by a Wald-test, but I
> don't know how exactly.
>

You can get a likelihood ratio test by also fitting a model without year and using anova() to compare the two models.

I think multiple people have written wald test functions. Mine is regTermTest in the "survey" package.

         -thomas



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