Estimate across-group heterogeneity of means and variances
hhetmodel(y, g)A vector (mu,t2,s20,nu0), where
mu is the mean of the group means
t2 is the variance of the group means
the the distribution of group variances is inverse-gamma(nu0/2,nu0 s20/2)
a numeric vector of data
a group membership vector, of the same length as y
Peter Hoff
This function estimates parameters in a hierarchical model for normally distributed groups, where the across-group model for means is normal and the across group model for variances is inverse-gamma.