Problem $18-4($Algo$)$

Here are the data for the past $21$ months for actual sales of a particular product:

$\backslash$table$[[,$LAST YEAR THIS YEAR,$],[$January$,335,280],[$February$,455,400],[$March$,465,350],[$April$,440,390],[$May$,418,400],[$June$,440,340],[$July$,440,395],[$August$,320,270],[$September$,360,400],[$October$,540,],[$November$,560,],[$December$,530,]]$

Develop a forecast for the fourth quarter using a three$-$quarter, weighted moving average. Weight the most recent quarter $0\mathrm{.}50,$ the second most recent $0\mathrm{.}25,$ and the third $0\mathrm{.}25.$ Do the problem using quarters, as opposed to forecasting separate months. $($Round your answer to $2$ decimal place:.$)$

Forecast for the fourth quarter