Thanks for the information. There was a discussion of different results obtained with the formula and data.frame methods for a paired t-test -- there are many threads, but one is at http://r.789695.n4.nabble.com/Paired-t-tests-td2325956.html#a2326291
david freedman -- View this message in context: http://r.789695.n4.nabble.com/data-frame-and-formula-classes-of-aggregate-tp3063668p3064177.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
