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:

Month Sales Forecast $1$ Forecast $2$

$1845810810$

$2840785790$

$3800800840$

$4820795800$

$5770805785$

$6840795796$

$7780785770$

$8835775770$

$9800835810$

$10860845825$

a$.$ Compute the MSE and MAD for each forecast. $($Round your answers to $2$ decimal places.$)$

b$.$ Compute MAPE for each forecast. $($Round your intermediate calculations to $5$ decimal places and final answers to $4$ decimal places.$)$

c$.$ Prepare a naive forecast for periods $2$ through $11$ using the given sales data. Compute each of the following; $(1)$ MSE, $(2)$ MAD, $(3)$ tracking signal at month $10,$ and $(4)2$s control limits$.($Negative values should be indicated by a minus sign. Round your answers to $2$ decimal places.$)$