Question $20$

$3\mathrm{.}13$ pts

During the past three weeks sales of a brand of medicine have been as follows:

$\backslash$table$[[$Week$,$Sales$],[1,71],[2,70],[3,69]]$

Using exponential smoothing with a smoothing constant of $\mathrm{.}10,$ forecast sales for week $4.($Note: Round answer to the nearest whole number of sales$)$

$12$

$71$

$70$

$69$

$72$