Two different forecasting techniques $($ F $1$ and F $2)$ were used to forecast demand for cases of bottled water. Actual demand and the two sets of forecasts are as follows:

$\backslash$table$[[,,$PREDICTED DEMAND$],[$Period$,$Demand,F$1,$F$2],[1,68,66,66],[2,75,68,68],[3,70,72,70],[4,74,71,72],[5,69,72,74],[6,72,70,76],[7,80,71,78],[8,78,74,80]]$

a$.$ Compute MAD for each set of forecasts. Given your results, which forecast appears to be more accurate? Explain.

b$.$ Compute the MSE for each set of forecasts. Given your results, which forecast appears to be more accurate?

c$.$ In practice, either MAD or MSE would be employed to compute forecast errors. What factors might lead a manager to choose one rather than the other?

d$.$ Compute MAPE for each data set. Which forecast appears to be more accurate?