4) A producer of various kinds of batteries has been producing "D" size batteries with a life expectancy of 87 hours. Due to an improved production process, management believes that there has been an...

4) A producer of various kinds of batteries has been producing "D" size batteries with a life expectancy of 87 hours. Due to an improved production process, management believes that there has been an increase in the life expectancy of their "D" size batteries. A sample of 36 batteries showed an average life of 88.5 hours. Assume from the past information that it is known that the standard deviation of the population is 9 hours.

A) Give the null and the alternative hypothesis.

B) Compute the test statistic.

C) At 99% confidence using the critical value approach, test management's belief.

D) What is the p-value associated with the sample results? What is your conclusion based on the p-value? Note α = 0.05.