[R] Help with Subtracting an effect from a Mixed Model
forister at life.bio.sunysb.edu
Sun Oct 30 17:02:31 CET 2005
I posted a similar question about a week ago, but haven't gotten any
replies -- I'm afraid that's because my previous question was too
vague. Let me try again with a more specific question, and I hope
someone can help. NOTE, I know I should be using the newer lme4
package, I just haven't had a chance to update my version of R yet, so
the question below relates to nmle.
I have data from a classical quantitative genetics experiment, with 33
sires mated each to 2 dams, with 15 progeny from each dam raised on 5
host plants (3 larvae per host). So the model I would like to run has
the following factors:
Dam [nested within sire] (random)
Host * Sire (random interaction)
Host * Dam [nested within sire] (random interaction)
This is the code I am using for that complete model:
I would like to try the model with and without each of those random
interactions (host*sire and host*dam-nested-within-sire).
WHAT IS THE SYNTAX FOR SUBTRACTING AN EFFECT FROM THE RANDOM STATEMENT?
I have tried:
But I get an "Invalid formula for groups" error.
Alternatively, I tried reorganizing the code, so that the interaction
would be left out. But there is no way to take out host*sire while
still leaving in host*dam nested within sire.
any help will be greatly appreciated!
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Matthew L Forister
Department of Ecology and Evolution
State University of New York at Stony Brook
650 Life Sciences Building
Stony Brook, New York 11794-5245
Email: forister at life.bio.sunysb.edu
Lab phone: (631) 632-8609
Fax: (631) 632-7626
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