Question 5 In order to estimate the difference between the average yearly incomes of the marketing managers of British Columbia and Ontario, the following data have been gathered: British Columbia Ontario Sample size n1 = 40 n2 = 45 Sample mean (in $1000) X1 = 72 X2 = 78 Sample standard deviation $1 = 6 $2 = 8 (in $1000) (a) Develop a 95% confidence interval for the difference between the average yearly incomes of the marketing managers of British Columbia and Ontario. (b) At 95% confidence, use the p-value approach to determine if the average the average yearly income of the marketing managers of British Columbia (wi) is significantly different from the average yearly income of the marketing managers of Ontario (12)