Either I am doing something very stupid or my R installation has a glitch. What am I missing? dd1 <- 50 dd2 <- 54 mean(dd1, dd2) [1] 50 # wrong (dd1 + dd2)/2 [1] 52 # correct aa <- c(48, 52, 56, 54, 52) mean(aa) [1] 52.4 # correct [[alternative HTML version deleted]]