1. Simulate the ARMA(1,1) process with gt 2 0.7, 69 = 0.5, and ,u = 100. Simulate 50 values but set aside the last 10 values to compare forecasts with actual values. (a) Use the rst 40 values as the dataset and nd the estimates for gt, 6 and a. (b) Using the estimated model, forecast the next ten values of the series. Plot the series together with the ten forecasts. Place a horizontal line at the estimate of the process mean. (c) Compare the ten forecasts with the actual values that you set aside. (d) Plot the forecast together with the 95 % forecast limits. (8) Repeat all the parts with a. new simulated series but using the same values of the pa rameters and the sample size