$[$Study Guide $-$ different numbers$]$ Weekly sales of copy paper at Cubicle Suppliers are provided in the table below. First, compute a two$-$period moving average for weeks $5,6,$ and $7.$ Compute the MAD

$\backslash$table$[[$Week$,$Sales $($cases$),],[1,,17],[2,,21],[3,,27],[4,,31],[5,19,],[6,17,],[7,,]]$

MAD$=6$

cannot be determined

MAD$=5$

MAD$=7$

MAD$=8$