Sales of tablet computers at Maria Gonzalez's electronics store in Washington D$.$C$.,$ over the past $10$ weeks are shown in the table below:

WEEK DEMAND WEEK DEMAND

$120629$

$221736$

$328822$

$437925$

$5251028$

Compute the following:

a$.$ Mean Forcast Error $($MFE$)$

b$.$ Mean absolute Deviation $($MAD$)$