C. Given the following data for demand at Southern Industries Ltd, calculate the forecast for periods 4-10 using a 3-period weighted moving average. The weight of 0.5, 0.3 and 0.2 are assigned to the most recent period respectively. Determine the MAD, (mean absolute deviation). Assume the control limit for the tracking signal is + 5. Is this a good forecast? Period Demand Forecast Error MAD 1 74 2 90 3 59 4 91 5 140 6 98 7 110 8 123 9 99 10 112 Table 1. (8 marks) (Total 20 marks) END OF SECTION A