The life in hours of a battery is known to be approximately

The life in hours of a battery is known to be approximately normally distributed with a standard deviation of 1.25 hours. A random sample of 10 batteries has a mean life of x = 40.5 hours. (a) Is there evidence to support the claim that battery life exceeds 40 hours? use ? = 0.05. (b) What is the probability to fail to reject ho if the population mean is 41 hours?

Solution

The life in hours of a battery is known to be approximately normally distributed with a standard deviation of 1.25 hours. A random sample of 10 batteries has a mean life of x = 40.5 hours.

(a) Is there evidence to support the claim that battery life exceeds 40 hours? use ? = 0.05.

Z = (xbar