[R] GLM with nested design

From: Giovanni Bacaro <bacaro_at_unisi.it>
Date: Sun 21 May 2006 - 01:02:40 EST

Dear list members,
I'd like to perform a glm analysis with a hierarchically nested design. In particular,
I have one fixed factor ("Land Use Classes") with three levels and a random factor ("quadrat") nested within Land Use Classes with different levels per classes (class artificial = 1 quadrat; class crops = 67 quadrats; and class seminatural = 30 quadrats). I have four replicates per each quadrats (response variable = species richness per plot)

Here some question about:
1) could I analize these data using the class "artificial" (i.e. I have only 1 level)?

2) using R I'd like perfor a glm analysis considering my response variable (count of species) with a Poisson distribution. How can I develop my model considering the nested nature of my design? I'm sorry but I don't know the right package to use.

3) for the Anova analysis I'd like use a post-hoc comparison between pairwise classes. What is the right procedure to do this? Is this analysis performed in R?


Dr. Giovanni Bacaro
UniversitÓ degli Studi di Siena
Dipartimento di Scienze Ambientali "G. Sarfatti"
Via P.A. Mattioli 4 53100 Siena
tel. 0577 235408
email: bacaro@unisi.it

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Received on Sun May 21 02:12:21 2006

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