Here's a sample script and a dataset attached to this email.
And here's the session information :
R version 2.15.1 (2012-06-22)
Platform: i386-pc-mingw32/i386 (32-bit)
locale:
[1] LC_COLLATE=French_Canada.1252 LC_CTYPE=French_Canada.1252
[3] LC_MONETARY=French_Canada.1252 LC_NUMERIC=C
[5] LC_TIME=French_Canada.1252
attached base packages:
[1] tcltk stats graphics grDevices utils datasets methods
[8] base
other attached packages:
[1] cem_1.1.5
combinat_0.0-8 randomForest_4.6-7 lattice_0.20-15
[5] nlme_3.1-108 MatchIt_2.4-21 MASS_7.3-23 rkward_0.6.0
loaded via a namespace (and not attached):
[1] grid_2.15.1 tools_2.15.1
thanks to look at it,
François Maurice