⑧ 2.8.Methods of Forecasting Trend Seasonal Series Period Demand MA(4) 1 10 2 20 3 26 4 17 5 12 18.25 6 23 18.75 7 30 19.5 8 22 20.5 21.75Period Demand MA(4) 1 10 2 20 3 26 4 17 5 12 18.25 6 23 18.75 7 30 19.5 8 22 20.5 21.75 2.8. Methods of Forecasting Trend Seasonal Series