Given the following data, Year t 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 Quarter 1 2 3 4 1 2 3 4 1 2 3 4 Sales 10 17 15 25 14 17 17 30 18 14 19 34 Weight 0,222 0,593 0,185 Sales R '000 a) Compute seasonal indices using a ratio to moving average method. b) Complete the sales decomposition. c) Use seasonality analysis to forecast the sales. d) Using the weights, evaluate the forecasting model. (15) (30) (10) (15)