[R] nested ANCOVA: still confused

Jeffrey Stratford stratja at auburn.edu
Tue Jan 24 17:33:49 CET 2006

Dear R-users,

I did some more research and I'm still not sure how to set up an ANCOVA
with nestedness.  Specifically I'm not sure how to express chicks nested
within boxes.  I will be getting Pinheiro & Bates (Mixed Effects Models
in S and S-Plus) but it will not arrive for another two weeks from our
interlibrary loan.

The goal is to determine if there are urbanization (purban) effects on
chick health (rtot) and if there are differences between sexes (sex) and
the effect of being in the same clutch (box).

The model is rtot = sex + purban + (chick)box.

I've loaded the package lme4.  And the code I have so far is

bb <- read.csv("C:\\eabl\\eabl_feather04.csv", header=TRUE)
bb$sex <- factor(bb$sex)
rtot.lme <- lme(bb$rtot~bb$sex, bb$purban|bb$chick/bb$box,

but this is not working.

Any suggestions would be greatly appreciated.



Jeffrey A. Stratford, Ph.D.
Postdoctoral Associate
331 Funchess Hall
Department of Biological Sciences
Auburn University
Auburn, AL 36849
FAX 334-844-9234

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