Hello all.
I was wondering if there is any way to adjust the denominator degrees of
freedom in lme(). It seems to me that there is only one method that can be
used. As has been pointed out previously on the list, the denominator
degrees of freedom given by lme() do not match those given by SAS
Contributions of code to provide alternative calculations of
denominator degrees of freedom are welcome :-)
I think it would be good to bear in mind that the use of the t and F
distributions for models with mixed effects is already an
approximation. If your design is such that you end up with a
Prof. Bates may be able to give us more recent references on this, but
the best literature I know on this is Pinhiero and Bates (2000)
Mixed-Effects Models in S and S-Plus (Springer, sec. 2.4). This
includes description of a simulate.lme function, which you can use to
generate random numbers
