[R] Mixed GLM methodology and execution question

Spencer Graves spencer.graves at pdf.com
Mon Mar 13 03:52:20 CET 2006

```	  Have you considered 'lmer' (split between the lme4 and Matrix
vignettes in the 'mlmRev' package.

hope this helps,
spencer graves
p.s.  If you are unfamiliar with vignettes, I suggest you consult
(http://finzi.psych.upenn.edu/R/Rhelp02a/archive/67006.html)

Ben Ridenhour wrote:

> Hi all,
> I have a question regarding how to properly analyze a data set and then how to perform the analysis in R.
>
> First,
> I have data that I would like to analyze using a mixed GLM (I think this is the most appropriate method, but I am unsure).  In a mixed model (y = X*beta+Z*gamma+epsilon), I would like to structure the variance matrices of gamma, G, and the error, R, to take advantage of all my information. The structure of the data is like this:
>
> Response Variable:
>  y = continuous response variable
>
>
>
> Predictor Variables:
>  x1 =  nominal treatment
>  x2 =  nominal group
>
>
>
> Random Variables:
>  z = nominal subgroup of x2, i.e. z is nested within x2
>
>
>
> Other variables(?; I'm not sure what exactly these are)
>  z1 = first continuous property of z
>  z2 = second continuous property of z
>  z3 =  third continuous property of z
>
>
> Presumably all the traits z1-z3 could potentially affect y, though I'm primarily interested in the model y=x1+x2+x1*x2. My wish is to put z in as a random variable and z1-z3 in the error matrix R.
>
> A small data sample  would be like
>
> x1    x2     z      z1      z2         z3         y
> L1   A1   S1   1.23   4.59   -1.02   100.45
> L2   A1   S1   1.23   4.59   -1.02   113.09
> L1   A1   S2   1.50   3.76    -0.06  119.21
> L2   A1   S2   1.50   3.76    -0.06  150.44
> L1   A2   S3   1.09   4.01    -1.50  109.18
> L2   A2   S3   1.09   4.01    -1.50  170.23
>  L1   A2   S4   1.01   3.70    -0.78  109.26
>  L2   A2   S4   1.01   3.70    -0.78  99.44
>
>
> What is correct way to put together my model/matrices for this situation?  How do accomplish such a task in R?
>
> Thanks,
> Ben
>
>
>
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>
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