[R] comparing length-weight regressions]

From: Rubén Roa-Ureta <rroa_at_udec.cl>
Date: Thu, 20 Mar 2008 09:40:28 -0400

saduria_at_hotmail.com wrote:
> I'd like to compare length-weight regressions among years. Any information would be appreciated.
> a. gray
> fisheries consultant

Your message is rather cryptic for a general statistical audience, whereas I'm sure in a fisheries group everybody would understand what you want.
Use a glm with family=Gaussian(link=log) for all data sets together (in original units) with year as a factor, then run the model again ignoring the year factor, and compare the different fits using anova(name of your glm objects) for a likelihood ratio test, or inspect the AICs for a non-frequentist model selection method.

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