The of a time series Y is the value of the time series k time periods in the past. O forecast growth rate O lag differenceSuppose you calculate a Theil's U value for some forecasting model (call it "Model A"), and you find it to be 1.23. What does this definitely tell you about the accuracy of your forecasting model? The mean squared error of Model A is 1.51. The RMSE of Model A is larger than the RMSE for the Naive 1 model. Forecasts made with Model A will be 23% less accurate than forecasts made with the Naive 2 model. The average error of Model A is 1.23