Brothers Willie and Billie each own a gas station for the same national chain. As brothers, they are very competitive. They held a contest to see who could do a better job forecasting sales for their station over the course of a year. Willie used a four-week moving average; Billie used a two-week moving average.

Willie's Petrol Park
Week	Sales (1000s of gallons)
1	17
2	21
3	19
4	23
5	18
6	16
7	20
8	18
9	22
10	20
11	15
12	22

Billie's Gasoline Grotto
Week	Sales (1000s of gallons)
1	85
2	84
3	76
4	69
5	54
6	80
7	100
8	54
9	88
10	80
11	60
12	66

a. Create the forecasts for each gas station.

b. Which error calculation would be the best to use in this contest? Why?

c. Who won the contest?