[R] Questions about glmms.

From: Horacio Montenegro <nepossiver_at_yahoo.com>
Date: Tue 08 Mar 2005 - 07:42:47 EST

        Hi,         

        I have a couple of questions related to glmm (glmmPQL in MASS and GLMM in lme4).

  1. is there some way do obtain the fitted values by group, similar to:

> predict(dbd.glmmPQL, dbd.cytdens,

+ type="response", level=0)

        where dbd.glmmPQL is the fitted model and dbd.cytdens is a data frame with a subset of the factors?         

        2) when I double-click on a saved workspace (.RData file) containing lme4 objects there is an error message and R crashes. Instead, if I load lme4 and then open the file, it loads smoothly. Is this a bug or just a feature? I'm working with R 2.0.1, lme4 0.9-2, Matrix 0.95-3, on windows 98. Unfortunately, I can’t provide the error message, as I don’t have R installed on this computer, but I can provide it later, if asked.         

        3) Has the result of anova(dbd.glmmPQL) or anova(dbd.GLMM) any meaning? If yes, what is it? I mean, if I do an anova(glmmPQL.object) or anova(GLMM.object), I do obtain an anova table that, for me (a biologist), is easily interpretable. I know that this question has been asked before, but, so far, I did not find a comprehensive answer. I've read Venables & Ripley MASS (2000), but glmmPQL is not mentioned there, and I do not have access to the later edition. Besides, in lme4 manual, under GLMM-class there is an anova method, but there are no further details explaining the method or its usage.

	cheers, 
	Horacio

--
Horacio Montenegro
PhD student in Genetics
Departamento de Genética e Evolução
UNICAMP
Campinas - SP - Brasil

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Received on Tue Mar 08 07:50:06 2005

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