The time taken by a man to deliver milk is normally distributed with, mean 12 minutes and standard deviation 2 minutes. He delivers milk everyday estimate the probability that he takes.

Question

(a) longer than 17 minutes
(b) between 9 and 13 minutes

Answer 1

Calculate Z=(x-μ)/σ
and look up the normal distribution table for the probabilities.

Answer 2

0.75