give explanation 10 A random walk time series has finite variance True/False 11. The ACF of s non-stationary time series falls to 0 relatively quickly (true or false 12 Which of the following is a useful property of forecasting residual purpose of calculating prediction intervals? 2. Residuals are normally distributed b. Residuals are uncorrelated c. Residuals have mean zero d. None of the above 14, What Is the consequence of forecasting residuals that don't have a. Prediction intervals are diffcult to calculate b.information is lett in the residuals that should be used c. Forecasts are biased d. None of the above 17. Given the regression equation y-hat=-15.6-3.8x the prediction will be _____ 16. The logarithmic transformation can make a time series statition a. stabilizing the mean B.stabilizing the variance C.)stabilizing both the mean and the variance d. stabilizing neither the mean nor the variance 20. What statistical test is used for testing the overall significance of the 2. Z test b t test C unit root test d Ftest