Problem $3$: $(7$ Points$)$

Two independent methods of forecasting based on judgment and experience have been prepared each month for the past $10$ months. The forecasts and actual sales are as follows:

$($a$).$ Compute the MSE and MAD for each forecast. Does either forecast seem superior? Explain.

$($b$).$ Compute MAPE for each forecast.

Compute the MSE and MAD for each forecast. Does either forecast seem superior? Explain.

Compute MAPE for each forecast.