Sigh. See FAQ 7.31. (As someone else has remarked on this list, 7.31 is by far the most frequently asked of all frequently asked questions.)
An aside: you should seriously consider upgrading your R installation; the current version is 3.6.1.
cheers, Rolf Turner -- Honorary Research Fellow Department of Statistics University of Auckland Phone: +64-9-373-7599 ext. 88276 ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.