The following data show the number of laptop computers sold each month at a retail store:

MonthUnit Sales

January ........................................................200

February ......................................................230

March ..........................................................225

April ............................................................240

May .............................................................210

June .............................................................180

July ..............................................................160

August.........................................................310

September....................................................320

October ........................................................270

November ....................................................250

December .....................................................300

a. Assuming the estimated trend from May to June was -4 and the forecast for June was 190, use trend-adjusted exponential smoothing with α= 0.3 and β=0.2 to forecast sales for each of the seven following months: July, August, September, October, November, December, and January.

b. Use regression for the data from January to June to create a forecast for each month from July to the following January.

c. Compare the two sets of forecasts generated in parts a. and b. Which forecast model produces a better MFE? MAD?