The forecast for the next period$($Jan$)$ using a$6-$month weighted average with weights of $0\mathrm{.}10,0\mathrm{.}10,0\mathrm{.}10,0\mathrm{.}20,0\mathrm{.}20,$ and $0\mathrm{.}30,$ where the heaviest weights are applied to the most recent month$=$

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$20\mathrm{.}7$ sales $($round your response to one decimal$$ place$).$

Part $5$

Using exponential smoothing with alpha $=0\mathrm{.}35$ and a September forecast of $18\mathrm{.}00,$ the forecast for the next period$($Jan$)=$

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$19\mathrm{.}21$ sales $($round your response to two decimal$$ places$).$