The following I do not understand, but then I did'nt really use S4 methods ...
> showMethods(plot) Function: plot (package graphics) x="ANY" x="lmList.confint" x="merMCMC" (inherited from: x="ANY") > plot(x=moda0MCMC) Error in as.double(y) : cannot coerce type 'S4' to vector of type 'double' > class(moda0MCMC) [1] "merMCMC" attr(,"package") [1] "lme4" Kjetil ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.