Use $3-$period moving average and exponential smoothing techniques to forecast demand for period $17.$ For exponential smoothing technique use $($alfa$)$ a $=0\mathrm{.}7$ and $($alfa$)$ a $=0\mathrm{.}4.$ Finally, see which forecast is more accurate by using mean absolute deviation $($MAD$)$ or MAPE techniques.

period: Sales:

$120$

$221$

$321$

$419$

$521\mathrm{.}5$

$622\mathrm{.}8$

$720\mathrm{.}75$

$823$

$922\mathrm{.}9$

$1018$

$1119$

$1217$

$1316\mathrm{.}8$

$1414$

$1513\mathrm{.}9$

$1616$

$17$