Displaying 1 result from an estimated 1 matches for "heterscedast".
2006 Jun 01
1
setting the random-effects covariance matrix in lme
Dear R-users,
I have longitudinal data and would like to fit a model where both the variance-covariance matrix of the random effects and the residual variance are conditional on a (binary) grouping variable.
I guess the model would have the following form (in hierarchical notation)
Yi|bi,k ~ N(XiB+Zibi, sigmak*Ident)
bi|k ~ N(0, Dk)
K~Bernoulli(p)
I can obtain different sigmas (sigma0 and