1. The error in forecasting for period T+1 at the end of period T is defined as e(T+1)= XT+ - XT+i(T). If the observations are independent random variables, X7+) Will be independent of X7+ (T) . Assume simple (single) exponential smoothing is applied to the constant process Xt = b+ &t, where var(&)= . Show that the variance of the forecast error, , satisfies the relationship N N 2- a