Using   .2 and   .2, find one-step-ahead forecasts for 1982 through 1989 and compute the MAD and MSE for the forecasts during this period. What is the sales forecast for the year 2000 made at the end of 1988? Based on the results of 1988, why might this forecast be very inaccurate?

b. By experimenting with various values of  and , determine the values of the smoothing constants that appear to give the most accurate forecasts.