Actual sales for January through April are shown below.

Observation

Month

Actual Sales $($A$)$

Forecasted Sales $($F$)$

$1$

January

$18$

$2$

February $23$

$3$

March $20$

$4$

April

$16$

$5$

May

Use exponential smoothing with an alpha factor $=0\mathrm{.}2$ to calculate the forecast for April from the above data. Assume the forecast for the initial period $($January$)$ is $18.$