Dear all,

I would like to get the posterior simulations of the variance components of a lmer() model with the mcmcsamp() function. How to do ?


*** For instance, below is the result of a lmer() fitting :

> fit
Linear mixed model fit by REML 
Formula: y ~ 1 + (1 | Part) + (1 | Operator) + (1 | Part:Operator) 
   Data: dat 
   AIC   BIC logLik deviance REMLdev
 97.55 103.6 -43.78    89.18   87.55
Random effects:
 Groups        Name        Variance Std.Dev.
 Part:Operator (Intercept) 2.25724  1.50241 
 Part          (Intercept) 3.30398  1.81769 
 Operator      (Intercept) 0.00000  0.00000 
 Residual                  0.42305  0.65043 
Number of obs: 25, groups: Part:Operator, 15; Part, 5; Operator, 3




*** Now I run mcmcsamp() : 


> mm <- mcmcsamp(fit, n=15000) 


*** I wasthinking that the posterior simulations of the residual variance are stored in the sigma node but this does not seem to fit the results of lmer() : 


> sigmasims <- mm@sigma[1,-(1:5000)]
> summary(sigmasims)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
 0.8647  1.4960  1.7040  1.7460  1.9480  3.7920 
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