$($a$)(5$ point$)[$True$/$False$]$ Two common measures of forecast accuracy are the mean absolute deviation $($MAD$)$ and the mean squared error $($MSE$),$ MAD always provides a more proper measure of error.

$($b$)(5$ point$)[$True$/$False$]$ In the exponential smoothing forecasting method, the choice of initial forecasts will not impact the performance of forecasting during the first several forecasting periods, because the impact of initial forecasts will be exponentially smoothed out.

$($c$)(5$ point$)[$True$/$False$]$ In the simple moving average method, we choose a smaller N value, when the data series has high uncertainty.

$($d$)(5$ point$)[$True$/$False$]$ The hiring costs and firing costs are not always linear function of the number of employees that are hired or fired respectively