$2$: $5-28$SALES $($$$1,000$s$)$MONTHSALES $($$$1,000$s$)$MONTH$11$January$14$August$14$February$17$September$16$March$12$October$10$April$14$November$15$May$16$December$17$June$11$January$11$JulySales of industrial vacuum cleaners at R$.$ LowenthalSupply Co$.$ over the past $13$ months are as follows:$($a$)$ Using a moving average with three periods, determine the demand for vacuum cleaners for next February.$($b$)$ Using a weighted moving average with three peri$-$ods, determine the demand for vacuum cleaners for February. Use $3,2,$ and $1$ for the weights of the most recent, second most recent, and third most recent periods, respectively. For example, if you were forecasting the demand for February, November would have a weight of $1,$ December would have a weight of $2,$ and January would have a weight of $3.($c$)$ Evaluate the accuracy of each of these methods.$($d$)$ What other factors might R$.$ Lowenthal consider in forecasting sales?