problem-5.21

problem-5.21  Making use of the scale() function we have
> x = scale(father.son$fheight)
> sum(abs(x) < 1)/length(x)
[1] 0.6753
> sum(abs(x) < 2)/length(x)
[1] 0.962
> sum(abs(x) < 3)/length(x)
[1] 0.999