Listed below are speeds $($mi$/$h$)$ measured from traffic on a busy highway. This simple random sample was obtained at $3\mathrm{.}30$ P$.$M$.$ on a weekday. Use the sample data to construct a $90\%$ confidence interval estimate of the population standard deviation.

Click the icon to view the table of Chi$-$Square critical values.

The confidence interval estimate is

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