[1] 3 5 7 9
> mean(x)[1] 6
> mean(x+2)[1] 8
> mean(3*x)[1] 18
> mean(3*x+2)[1] 20
> x-mean(x)[1] -3 -1 1 3
> (x-mean(x))^2[1] 9 1 1 9
> sum((x-mean(x))^2)/length(x)[1] 5
> ((x+2)-mean(x+2))^2[1] 9 1 1 9
> sum(((x+2)-mean(x+2))^2)/length(x)[1] 5
> (3*x-mean(3*x))^2[1] 81 9 9 81
> sum(((3*x)-mean(3*x))^2)/length(x)[1] 45
> sum(((3*x+2)-mean(3*x+2))^2)/length(x)[1] 45
> x=c(1,2,3,3,3,4,5,6,8) > x[1] 1 2 3 3 3 4 5 6 8
> median(x)[1] 3
getmode <- function(v) { uniqv <- unique(v) uniqv[which.max(tabulate(match(v, uniqv)))] } > getmode(x)[1] 3
> x=c(1,4,2,rep(3,3),4,5,6,8) > x[1] 1 4 2 3 3 3 4 5 6 8
> sort(x)[1] 1 2 3 3 3 4 4 5 6 8
> length(x)[1] 10
> x_sort=sort(x) > x_sort[1] 1 2 3 3 3 4 4 5 6 8
> sum(x_sort[5]:x_sort[6])/2[1] 3.5
> median(x)[1] 3.5
> getmode(x)[1] 3
