Use the gas prices data set below to calculate a $3$

$-$month Weighted Moving Average $($WMA$)$ forecast for the average gas prices and predict the average retail gasoline price for September $2007.$ Use the weights of $0\mathrm{.}6,0\mathrm{.}3,$ and $0\mathrm{.}1$

for the $3$

$-$month WMA, where the first weight is used for the most recent month and the last weight is used for the least recent month. Round your answer to two decimal places, if necessary.

Month$-$Year Average Gas Price

Jan$-07$ $$2\mathrm{.}289$

Feb$-07$ $$2\mathrm{.}323$

Mar$-07$ $$2\mathrm{.}609$

Apr$-07$ $$2\mathrm{.}891$

May$-07$ $$3\mathrm{.}187$

Jun$-07$ $$3\mathrm{.}102$

Jul$-07$ $$3\mathrm{.}011$

Aug$-07$ $$2\mathrm{.}834$