Question

Two independent methods of forecasting based on judgment and experience have been prepared each month for the past 10 months.

The forecasts and actual sales are as follows:

Month Sales Forecast 1 Forecast 2

1 771 774 772

2 790 789 791

3 794 792 792

4 776 776 775

5 772 773 772

6 770 771 772

7 761 761 765

8 774 778 778

9 792 792 794

10 794 798 797

a. Compute a tracking signal for the 10th month for each forecast using the cumulative error for months 1 to 10. Use action limits of ± 4. Is there bias present? (Do not round your intermediate calculations. Round your answers to 2 decimal places. Negative amounts should be indicated by a minus sign.)

Forecast Tracking Signal Bias Method 1 Method 2

b. Compute 2s control limits for each forecast. (Do not round your intermediate calculations. Round your answers to 2 decimal places.)

Forecast Control Limits Method 1 Method 2

Answer 1

part a)

Part b)