The Bureau of Labor Statistics reported that the average yearly income of dentists in the year 2017 was $110,000. A sample of 81 dentists, which was taken in 2019, showed an average yearly income of $120,000. Assume the standard deviation of thepopulationof dentists is $36,000.

a. We want to test to determine if there has been a significantincreasein the average yearly income of dentists. The null and the alternative hypotheses.

b. What is the value of the test statistic.

c. Determine thep-value; and at 5% significance level, test the hypotheses.

d. State your conclusion in the context of the problem