Suppose That Replacement Times for Washing Machines Are Normally Distributed

Multiple Choice

Suppose that replacement times for washing machines are normally distributed with a mean of 9.3 years and a standard deviation of 1.1 years. Find the probability that 70 randomly selected washing machines will have a mean replacement time less than 9.1 years.

A) 0.4357
B) 0.0714
C) 0.0643
D) 0.4286