Hey, > To the best of my knowledge, this forum is not for help with homeworks.
Probably it is, but it only works for those who can disguise their homework as Real Problems :) It might be good excercise to have a read of http://www.catb.org/~esr/faqs/smart-questions.html though. Cheers, Tsjerk -- Tsjerk A. Wassenaar, Ph.D. post-doctoral researcher Molecular Dynamics Group * Groningen Institute for Biomolecular Research and Biotechnology * Zernike Institute for Advanced Materials University of Groningen The Netherlands ______________________________________________ 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.