$($a$)$ Use two$-$month moving average and use trend projection method to forecast the coal sales. Based on the analysis in part $($a$)$ and $($b$),$ which method moving average, or trend projection provides the better forecast? Explain. Do Not Rearranged Data!

$\backslash$table$[[$Weather Index,$\backslash$table$[[$Coal sales$],[($Millions of Tons$)]]],[x_{?},Y_{?}$