The Cat Creek Mining Company mines and ships coal. It has experienced the following demand for coal during the past 8 years:
Year ..... Coal Sales (tons)
1 ....... 4,260
2 ....... 4,510
3 ...... 4,050
4 ....... 3,720
5 ...... 3,900
6 ...... 3,470
7 ...... 2,890
8 ....... 3,100
Develop an adjusted exponential smoothing model (α = .30, β = .20) and a linear trend line model and compare the forecast accuracy of the two by using MAD. Indicate which forecast seems to be more accurate.