[R-sig-eco] a mixed-effects model?

[yann clough]

Dear Lara,

you introduce random effects if you have grouped or repeated-measures 
data, to account for the resulting covariance/non-independence, or if 
you are interested in modelling variability at different hierarchical 
levels.
 From your description at least, all your data points seem independent 
of each other.

qinit is a covariate, i.e.:
you probably want to model this as:

glm(clutchsize~treatment*species+qinit)

HTH,
Yann


-- 
Dr. Yann Clough

Agroecology
Department of Crop Sciences
Göttingen University
Grisebachstrasse 6
Room 3.131 (3rd floor)
D-37077 Göttingen (Germany)
Tel.: (+49) 0551 3922358
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