[R] Variance Functions in lme

Rick Bilonick rab45+ at pitt.edu
Thu Nov 9 20:43:54 CET 2006

Using the weight argument with a variance function in lme (nlme), you
can allow for heteroscedasticity of the within-group error. Is there a
way to do this for the other variance components? For example, suppose
you had subjects, days nested within subjects, and visits nested within
days within subjects (a fully nested two-way design) and you had, say
men and women subjects. Could you allow for differences in the variance
components for men and women?

Rick B.

More information about the R-help mailing list