The Bee line Café is well known for its popular homemade ice cream, which it makes in a small plant in back of the café. People drive long distance to buy the ice cream. The two ladies who own the café want to develop a forecasting model so they can plan their ice cream production and determine the number of employees they need to sell ice cream in the café. They have accumulated sales records for their ice cream for the past 12 quarters.

Develop:

a) an exponential smoothing model (= 0.50)

b) moving average model (k = 4)

c) a trend model; and

d) a seasonally adjusted model to forecast demand.

Assess the accuracies of the models by using Bias, MAD, MAPD.

Quarter Ice Cream Sales (gal)

1 350

2 510

3 750

4 420

5 370

6 480

7 860

8 500

9 450

10 550

11 820

12 570