The values in a$x do look numeric. What do you get from: class(a$x)
If the result is "factor", as it was for your ft$trait3 variable (and I hope that a$x is the same variable with a different name), then at least one of those values must have been read in as non-numeric. The possible reasons for this are many as Jeff noted and may be a non-printing character that has crept into your original data file. If your data set is as small as your example, I would start by loading the original data file into a hex editor and looking for a character that shouldn't be there. I once had to write a program in C that scanned very large files of customer data to find just such troublemakers and tell me where they were. Jim ______________________________________________ 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.
