"Probability of exactly 75 heads" f(k) = choose(n,k) p^k (1-p)^(n-k) n = 100 p = 1/2 float(f(75)) F(x) = sum(k,0,x,f(k)) "Verify symmetry" check(F(25) == 1 - F(74)) "ok" "Probability that number of heads is beyond 5 standard deviations of the mean" float(2 F(25)) "Probability that number of heads is within 1 standard deviation of the mean" float(F(55) - F(45)) Run