Random covariates with common variance
Hello everyone, I can not find in the documentation how to fit the following model with lmer, any help would be much appreciated: Suppose I have a set of three covariates z1, z2, z3 that I want to fit as random effects. Their coefficients U=(u1,u2, u3) have distribution: U~N(0,sig.sq_u*I) Where sig.sq_u is a scalar, I is the Identity matrix of order 3. I can fit a model with an unstructured covariance matrix on U, and with independent heteroskedastic distributions on the components of U, but cannot find a way of fitting what I need. Any pointers/suggestion/comments? Thanks! JP
============================= Juan Pedro Steibel Assistant Professor Statistical Genetics and Genomics Department of Animal Science & Department of Fisheries and Wildlife Michigan State University 1205-I Anthony Hall East Lansing, MI 48824 USA Phone: 1-517-353-5102 E-mail: steibelj at msu.edu