Weekly sales of copy paper at Cubicle Suppliers are provided in the table below. Compute a three-period moving average forecast, a four-period moving average forecast, and exponential smoothing forecasts with smoothing constants of 0.2 and 0.4 for weeks 5, 6, and 7. The forecast for week 4 is 22 cases. Compute the MAD for each forecasting methods. Which model is the most accurate? Forecast week 8 with the most accurate method.

Week Sales (cases)

1 17

2 23

3 26

4 22

5 28

6 17

7 23