Q3. The life of a battery is known to be approximately normally-distributed, with standard deviation = 1.25 hours. A random sample of 10 batteries has a mean life of 40.5 hours.

1.Is there any evidence to support the claim that the battery life exceeds 40 hours? Use = 0.05.

2.What is the P-value for the test?

3.What is the -error for the test if the true mean life is 42 hours?

4.What sample size would be required to ensure that -error does not exceed 10% if the true mean life is 44 hours?