Refer to the monthly gold prices, Exercise 14.31. Two models were used to forecast the monthly 2015 gold prices: an exponential smoothing model with w = .5 and a Holt model with w = .5 and v = .5.
a. Use MAD, MAPE, and RMSE criteria to evaluate the two models' accuracy for forecasting the monthly 2015 values using the 2009-2014 data.
b. Use the MAD, MAPE, and RMSE criteria to evaluate the two models' accuracy when making the 12 one-step-ahead forecasts, updating the models with each month's actual value before forecasting the next month's value.