Willie's Petrol Park Billie's Gasoline Grotto Week Sales (1000s of gallons) Week Sales (1000s of gallons) Brothers Willie and Billie each own a gas station for the same national chain. As brothers, they are 17 1 85 very competitive. They held a contest to see who could do a better job forecasting sales for their station 21 84 over the course of a year. Willie used all-previous values method; Billie used a two-week moving 19 76 average method. (15 points) 23 69 18 54 a. Create the forecasts for each gas station. 16 5 6 0 J a UI A W N 80 b. Which error calculation MSE or MAPE would be the best to use in this contest? Why? 5 - 0 6 0 J a UI A W N 20 100 18 54 c. Who won the contest? 22 88 20 80 15 11 60 22