Use Excel file Gasoline Prices to develop the following models:$-$

$($a$)$ Develop spreadsheet models for forecasting prices using simple $2-$period and $3-$period moving averages and simple exponential smoothing with smoothing constants of $0\mathrm{.}2$ and $0\mathrm{.}4(1\mathrm{.}25$ each, total $6$ points$).$

$($b$)$ Using MAD as guidance find the best forecasting method among the $4$ calculations from $($a$)(4$ points$).$