Calculate$($a$)$ MAD and$($b$)$ MSE for the following forecast versus actual sales$$ figures:

$$

Forecast

$100$

$110$

$120$

$130$

Actual

$95$

$108$

$123$

$130$

Part $2$

$$a$)$ MADequals$=$enter your response here $($round your response to one decimal$$ plac