Question

A production manager at a wall clock company wants to test their new wall clocks. The designer claims they have a mean life of 1717 years with a variance of 2525.

If the claim is true, in a sample of 3939 wall clocks, what is the probability that the mean clock life would differ from the population mean by less than 22 years? Round your answer to four decimal places.

Answer 1

Solution :

= / n = 5 / 39 = 0.8006

= P[(-2) / 0.8006 < ( - ) / < (2) / 0.8006)]

= P(-2.50 < Z < 2.50)

= P(Z < 2.50) - P(Z < -2.50)

= 0.9938 - 0.0062

= 0.9876

Probability = 0.9876