Oops. please ignore my first reply. I mis-read the question and the code was messed up because I change the object name in the middle. Sorry for any confusion. :)
-- ====================================== T.K. (Tae-kyun) Kim Ph.D. student Department of Marketing Marshall School of Business University of Southern California ====================================== [[alternative HTML version deleted]] ______________________________________________ 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.