Problem $956509$: Use the following data to calculate the MAD and MSE of the forecasts.

Period Demand

Forecasts

$256$

$2$

$3$

$4$

$5$

$270$

$248$

$265$

$244$

$258$

$256$

$244$

$241$

Period

Absolute Error

$1$

$2$

$3$

$4$

$5$

Calculate the mean absolute deviation $($MAD$)$ of the forecasts?

Calculate the mean squared errors $($MSE$)$ of the forecasts?