Group Averages Over Level Combinations of Factors
x are averaged, where each subset consist of those
observations with the same factor levels.
ave(x, …, FUN = mean)
- A numeric.
- Grouping variables, typically factors, all of the same
- Function to apply for each factor level combination.
A numeric vector, say
y of length
g1, g2, e.g.,
y[i] is equal to
FUN(x[j], for all
g1[j] == g1[i] and
g2[j] == g2[i]).
require(graphics) ave(1:3) # no grouping -> grand mean attach(warpbreaks) ave(breaks, wool) ave(breaks, tension) ave(breaks, tension, FUN = function(x) mean(x, trim = 0.1)) plot(breaks, main = "ave( Warpbreaks ) for wool x tension combinations") lines(ave(breaks, wool, tension ), type = "s", col = "blue") lines(ave(breaks, wool, tension, FUN = median), type = "s", col = "green") legend(40, 70, c("mean", "median"), lty = 1, col = c("blue","green"), bg = "gray90") detach()