Re: [R] how to specify two variance effects in gls

[stephenb]

I got the answer:

weights=varComb(varFixed(~1/n),varPower(~Age))



Bond, Stephen-2 wrote:
 
 Hello everybody,
 
 I have a dataset where each row has number of subjects and that gives me
 natural weights for the variance function. Additionally I see that
 variance increases with Age, which is a regressor.
 So using gls I have
 
 
 
 weights=varFixed(~1/n)
 
 but don't know how to include the extra effect of the regressor.
 Fitted values show a quadratic curve vs. age, not sure if that helps.
 
 Thanks everybody.
 Stephen
 
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[R] how to specify two variance effects in gls

[Bond, Stephen]

Hello everybody,

I have a dataset where each row has number of subjects and that gives me 
natural weights for the variance function. Additionally I see that variance 
increases with Age, which is a regressor.
So using gls I have



weights=varFixed(~1/n)

but don't know how to include the extra effect of the regressor.
Fitted values show a quadratic curve vs. age, not sure if that helps.

Thanks everybody.
Stephen

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.