[R] nlme and start=list()

Douglas Bates bates at stat.wisc.edu
Fri Nov 22 22:42:03 CET 2002


Douglas Bates <bates at stat.wisc.edu> writes:

> Andrew Beckerman <a.p.beckerman at stir.ac.uk> writes:
<snip>
> > The data are
> > Frames = speed of flight (20-50)
> > Manlength = tail length (-20,0)
> > ID = individual (14 of them)
> > 
> > each individual has experienced each of 6 tail lengths in the range
> > above and we are interested in the shape of the relationship between
> > speed and manipulation.
> > 
> > 
> > using the following approach based on the Venables and Ripley (3rd ed)
> > examples with the Sitka data set
<snip>
> First the good news - you don't need to use nlme to fit a polynomial
> model.  A polynomial is linear in the coefficients so you can use lme,
> which is much easier than nlme.
> 
> lme(Frames ~ Manlength + I(Manlength^2), random = Manlength)

Oops - I got that wrong.  The random argument should be
  random = ~ Manlength | ID
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