Given the following sales data:

week $1$: $70$

week $2$: $76$

week $3$: $89$

week $4$: ${77}^{***}$

week $5$: $84$

Forecast sales for week $6$ using a $3-$period weighted moving average forecast using the following weights:

$0\mathrm{.}6,0\mathrm{.}3,0\mathrm{.}1$

Your Answer: