Consider the Costello Music Company problem in exercise 48. The quarterly sales datafollow.Total YearlyYear Quarter 1 Quarter 2 Quarter 3 Quarter 4 Sales XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX...

Consider the Costello Music Company problem in exercise 48. The quarterly sales data follow. Total Yearly Year Quarter 1 Quarter 2 Quarter 3 Quarter 4 Sales 1 4 2 1 5 12 2 6 4 4 14 28 3 10 3 5 16 34 4 12 9 7 22 50 5 18 10 13 35 76 a. Use the following dummy variables to develop an estimated regression equation to account for any seasonal and linear trend effects in the data: Qtr1  1 if Quarter 1, 0 otherwise; Qtr2  1 if Quarter 2, 0 otherwise; and Qtr3  1 if Quarter 3, 0 otherwise. b. Compute the quarterly forecasts for next year