Problem $3-22($Algo$)$

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.

Note: Round your answers to $2$ decimal places.

b$.$ Compute MAPE for each forecast.

Note: Round your intermediate calculations to $5$ decimal places and final answers to $4$ decimal places.

MAPE F$2$

c$.$ Prepare a naive forecast for periods $2$ through $11$ using the given sales data. Compute each of the following;

MSE,

MAD,

Tracking signal at month $10,$ and

$2s$ control limits$.$

Note: Negative values should be indicated by a minus sign. Round your answers to $2$ decimal places.