The last seven weeks of demand at a new car dealer are shown below.

Week Sales

1 36

2 60

3 48

4 70

5 6 0

6 64

7 72

a) Use a three-period weighted moving average to determine a forecast for the week 4, week 5, week 6, and week 7 using weights of 2, 3, and 5 as shown in the table given below.Calculate the MAD.

Weights Applied Time Period

5 Last week

3 Two weeks ago

2 Three weeks ago

Week Sales Forecasting

1 36

2 60

3 48

4 70

5 60

6 64

7 72

b) Use exponential smoothing with an alpha of 0.5 to determine a forecast from week 2 to week 7 with an initial forecast of 18 for Week 1. Calculate the MAD.