Also, and possibly more constructively, when you get an error like > CI.c = predict(mod2, data.frame( `plant-density` = x), interval = 'c') # fail Error in eval(predvars, data, env) : object 'plant-density' not found
you should check your assumptions. Does "newdata" actually contain a columnn called "plant-density": > head(data.frame( `plant-density` = x)) plant.density 1 65.00000 2 65.11912 3 65.23824 4 65.35736 5 65.47648 6 65.59560 > I.e., it doesn't. So check help for data.frame and looking for something with names. > On 1 Dec 2023, at 01:47 , Bert Gunter <bgunter.4...@gmail.com> wrote: > > "Thank you Rui. I didn't know about the check.names = FALSE argument. >> Another good reminder to always read help, but I'm not sure I understood >> what help to read in this case" > > ?data.frame , of course, which says: > > "check.names > > logical. If TRUE then the names of the variables in the data frame are > checked to ensure that they are syntactically valid variable names and > are not duplicated. If necessary they are adjusted (by make.names) so > that they are. " > > -- Bert > > ______________________________________________ > 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. -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ 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.