Question

The diameter of a pipe is normally distributed, with a mean of 0.8 inch and a variance of 0.0025. What is the probability that the diameter of a randomly selected pipe will exceed 0.9 inch?

Answer 1

0.02275

Explanation:

Standard deviation is the square root of variance

Standard deviation= Square(0.0025)= 0.05

Because of the normally distributed, the z- score for 0.9 inches is:

(0.9-0.8)/0.05= 2

-> P(x<= 0.9)= P(2) = 0.97725

-> P (x>= 0.9)= 1-0.97725 = 0.02275