In order to estimate the difference between the average yearly incomes of marketing managers in the East and West of the United States, the following information was gathered. Sample Size East 40 Sample Mean 72 (in $1000) Sample Standard Deviation 6 (in $1000) Test the following hypotheses: Ho: HEast West Ha: HEast West a. Calculate the value of the test statistic. (Round to two decimal places) -3.94 b. What is the p-value? (Round to four decimal places) At a 1% significance level the decision is to West 45 78 (in $1000) 8 (in $1000)