Consider the following data. We want to monitor the forecasts.

Period..............Demand............Forecasts ......

1...................260....................-- ......

2...................256....................260 .....

3...................288....................256 ......

4...................281....................288 ......

5...................306....................281

Calculate the UCL and LCL for the appropriate control chart? Calculate the cumulative error, MAD, and tracking signals.

Error of period 2

Error of period 3

Error of period 4

Error of period 5

Overal MSE:

UCL to monitor the magnitude of the errors

LCL to monitor the magnitude of the errors

Are the errors in control? Yes No

Cumulative error up to period 2

Cumulative error up to period 3

Cumulative error up to period 4

Cumulative error up to period 5

MAD up to period 2 MAD up to period 3

MAD up to period 4 MAD up to period 5

Tracking signal of period 2

Tracking signal of period 3

Tracking signal of period 4

Tracking signal of period 5

Based on your tracking signals, are the forecasts biased? Yes No