On Mon, 1 Mar 2010 14:23:04 -0500 Liaw, Andy <andy_liaw at merck.com> wrote: > Indeed this is one of the (few, I believe) traps of R, Oh, no; there are many more: http://www.burns-stat.com/pages/Tutor/R_inferno.pdf :-) -- Karl Ove Hufthammer