The state test scores for $12$ randomly selected high school seniors are shown on the right. Complete parts $($a$)$ through $($c$)$ below.

$1420$

$1220$

$986$

Assume the population is normally distributed.

$697$

$728$

$838$

$730$

$749$

$549$

$626$

$1448$

$946$

$($a$)$ Find the sample mean.

$\stackrel{}{x}=($Round to one decimal place as needed.$)$

$($b$)$ Find the sample standard deviation.

$s=($Round to one decimal place as needed.$)$

$($c$)$ Construct a $90\%$ confidence interval for the population mean $.$

A $90\%$ confidence interval for the population mean is $$

$($Round to one decimal place as needed.$)$