[R-sig-ME] New alpha version of lme4 code on R-forge

Douglas Bates bates at stat.wisc.edu
Mon Mar 10 23:44:54 CET 2008

I have just uploaded a new version of the lme4 package to
R-forge.R-project.org.  I hope that binary packages for
lme4_0.999875-6 will be available tomorrow.

This version has an mcmcsamp function for linear mixed models fit by
lmer.  I have not yet incorporated the Metropolis-Hastings step for
sampling from the fixed effects and random effects in generalized
linear mixed models or nonlinear mixed models.

I have methods for the HPDinterval function for these objects.  You
can apply it to the entire sample or to the fixef slot only or to the
sigma slot only.  There is another slot called ST from which the
variances and covariances of the random effects can be derived.

I think I found a glich in earlier versions of mcmcsamp that made them
overly conservative.  When I sampled from the conditional distribution
of the sigma parameter I think I used the wrong number of degrees of
freedom for the chi-square distribution.  I have modified that and
think the results look more like they should.  However, I would
appreciate feedback on whether these results look sensible to others.

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