Message-ID: <loom.20111213T205232-947@post.gmane.org>
Date: 2011-12-13T19:53:16Z
From: Ben Bolker
Subject: Should I use nls for this?
xfei <xiaoyifei <at> gmail.com> writes:
> I have a dataset with the following properties:
> Y_i ~ N(mu_i, theta * (mu_i)^2)
> ln(mu_i) = B'Xi
>
> theta and beta's are the parameters here.
>
> I want to come up with a model to fit the data with the above property and
> test that model on the built in R dataset quine.
>
> Does nls() make sense in this case? Or is there any existing R package which
> can fit this model?
You don't need nls():
see ?gls, ?varCorr, ?varPower in the nlme package.