Sales of vegetable dehydrators at Bud Banis?s discount department store in St. Louis over the past year are shown below. Management prepared a forecast using a combination of exponential smoothing and its collective judgment for the 4 months (March, April, May, and June of 2010):
(a) Compute MAD and MAPE for management?s technique.
(b) Do management?s results outperform (i.e., have smaller MAD and MAPE than) a naive forecast?
(c) Which forecast do you recommend, based on lower forecast error?