$1)$ Develop a forecast for the sales in August of Year $5$ by using three different forecasting techniques: Three$-$month simple moving average, Weighted moving average with weights $0\mathrm{.}5,0\mathrm{.}3,0\mathrm{.}2($the weight $0\mathrm{.}5$ is given to the most recent observation$),$ and Exponential smoothing method with a smoothing constant of $0\mathrm{.}3.(15$ points$)$