A study says the mean time to recoup the cost of bariatric surgery is 3 years. You randomly select 25 bariatric surgery patients and find that the mean time to recoup the cost of their surgeries is 3.3 years. Assume the population standard deviation is 0.5 year and the population is normally distributed. Is there enough evidence to doubt the study’s claim at α = 0.01? Use a P-value.

a. Identify the claim. Then state the null and alternative hypotheses.

b. Identify the level of significance α.

c. Find the standardized test statistic z.

d. Find the P-value.

e. Decide whether to reject the null hypothesis.

f. Interpret the decision in the context of the original claim.