Hi Michael, Try
fit <- lm(ozone~garden, data = test) summary(fit) See ?lm for more details. HTH, Jorge.- On Sat, Oct 20, 2012 at 8:26 AM, Michael Grant <> wrote: > New installation seems to have behavior I cannot figure out. Here is > illustrative sequence where I load a small data set (test) from Crawley's > files and try to run a simple linear model and get an error message. > Oddly, R reports that the variable 'test$ozone' is numeric while, after > attaching test, the variable ozone is not numeric. Can someone please > help? This behavior is occurring with multiple data sets loaded from > outside R. Thank you in advance. > Michael Grant > > > Example: > > test > ozone garden > 1 3 A > 2 5 B > 3 4 A > 4 5 B > 5 4 A > 6 6 B > 7 3 A > 8 7 B > 9 2 A > 10 4 B > 11 3 A > 12 4 B > 13 1 A > 14 3 B > 15 3 A > 16 5 B > 17 5 A > 18 6 B > 19 2 A > 20 5 B > > is.data.frame(test) > [1] TRUE > > is.numeric(test$ozone) > [1] TRUE > > is.factor(test$garden) > [1] TRUE > > lm(ozone~garden) > Error in model.frame.default(formula = ozone ~ garden, drop.unused.levels > = TRUE) : > invalid type (list) for variable 'ozone' > > > attach(test) > > is.numeric(ozone) > [1] FALSE > > is.numeric(test$ozone) > [1] TRUE > > [[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. > [[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.
