Consider the sales data for Computer Success given in Problem 7.
a. Use a 3-month weighted moving average to forecast the sales for the months April through December. Use weights of (4/8), (3/8), and (1/8), giving more weight to more recent data.
b. Use exponential smoothing with a - 0.6 to forecast the sales for the months April through December. Assume that the initial forecast for January was $3,200. Start error measurement in April.
c. Compare the performance of the two methods by using the mean absolute deviation as the performance criterion, with error measurement beginning in April. Which method would you recommend?
d. Compare the performance of the two methods by using the mean absolute percent error as the performance criterion, with error measurement beginning in April. Which method would you recommend?
e. Compare the performance of the two methods by using the mean squared error as the performance criterion, with error measurement beginning in April. Which method would you recommend?