R help - Mar 2010 - Correct nested design for GLM

Hi,
 I am currently running the following negative binomial GLM:

glm89.nb <- glm.nb(AvGUD ~ Year*Trt*Micro + (0 + Micro/Trt/Year))

where Year has 3 levels, Trt has 2 levels, and Micro has 3 levels.
>From what I have read the above model has a 3 way interaction
(Year*Trt*Micro), and Micro is nest within Trt and Trt is nested with Year
(0 + Micro/Trt/Year).
I was hoping someone could confirm that this is actually what the model is
running?

Thank you very much for your time,
Rebecca

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I guess your model specification is incoherent. It's seems to me that you
incorporated some kind of lmer() style with "(0 + Micro/Trt/Year)"
term.
Consider the toy data and code below. Nesting model is m2. Models m1 and m3
are the same so showing that terms in brackets don't are used.

da <- expand.grid(A=factor(1:3), B=factor(1:3))[rep(1:9, 3),]
da$y <- rnbinom(da$A, size=10, prob=0.5)

m1 <- glm.nb(y~A*B, data=da)
anova(m1)

m2 <- glm.nb(y~A/B, data=da)
anova(m2)

m3 <- glm.nb(y~A*B+(A/B), data=da)
anova(m3)

Bests.
Walmes Zeviani.

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..(....)... 0ooo...                              Walmes Zeviani
...\..(.....(.....)...     Master in Statistics and Agricultural
Experimentation
....\_)..... )../....       walmeszeviani at hotmail.com, Lavras - MG, Brasil
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