Use Simpson's Rule $to$ determine the average temperature $in$ a museum over $a3-$hour period $if$ the temperatures $(in$ degrees

Celsius$)$ recorded $at15-$min intervals are $21,21\mathrm{.}4,21\mathrm{.}5,21\mathrm{.}8,21\mathrm{.}6,21\mathrm{.}1,20\mathrm{.}8,20\mathrm{.}7,20\mathrm{.}9,21\mathrm{.}3,21\mathrm{.}1,21\mathrm{.}5,21\mathrm{.}2.$

$(Use$ decimal notation. Give your answer $to$ three decimal places.$)$

$T_{\text{a}\text{v}\text{e}}$