I know commands like xtabs and table allow a user to do cross-tabulation For example the following command generates a pivot table that shows the number of cars that have the same number of gears and cylinders.
>xtabs(~cyl+gear,data =mtcars) gear cyl 3 4 5 4 1 8 2 6 2 4 1 812 0 2 > We can extend the formula so it could show the sum of the horse power for the cars in each bin >xtabs(hp~cyl+gear,data =mtcars) gear cyl 3 4 5 4 97 608 204 6 215 466 175 82330 0 599 > I am now wondering, is it possible to calculate the mean of horse powers for cars in each bin? for example something like this xtabs(mean(hp)~cyl+gear, data = mtcars) Thank you Mark ______________________________________________ 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.
