"D" size batteries produced by MNM Corporation have had a life expectancy of 87 hours. Because of an improved production process, it is believed that there has been an increase in the life expectancy of its "D" size batteries. A sample of 36 batteries showed an average life of 90 hours. Assume from past information that it is known that the standard deviation of the population is 9 hours.

a. Define the hypotheses for this problem

b. Compute the test statistic.

c. What is the p-value associated with the sample result?

d.What is your conclusion based on the p-value? Leta= .05