In 2011 a sruvey by the American Bar Association indicated that the average yearly income of attorneys was $110,000. A sample of 81 attorneys was taken in 2012 and it reflected an average yearly income of $120,000. Assume the standard deviation of the population of attorneys in 2012 is $36,000.
We want to test to determine if there has been a significant increase in the average yearly income of attorneys. Provide the null and the alternative hypotheses.
Compute the test statistic.
Determine the p-value; and at 95% confidence, test the hypotheses.