(data heights 71 71 72 73 66 72 70 71 68 71 72 69 72 63 76 75 61)
(mean heights)
(sd heights)
(histogram heights)
(plot (kernel-dens heights :xvals (grid 48 84 100)))
(func rho(x) x ^ 2)
(simp rho 0 2 100)