Thanks. I use the bootstrap() function from the bootstrap package. Let me try it again to see if I get any luck :) -- View this message in context: http://r.789695.n4.nabble.com/Error-in-apply-x2-1-diff-dim-X-must-have-a-positive-length-tp4382435p4384608.html Sent from the R help mailing list archive at Nabble.com.