number 36

Listed below are speeds(mi/h) measured from traffic on a busy highway. This simple random sample was obtained at3:30 P.M. on a weekday. Use the sample data to construct a 95% confidence interval estimate of the population standard deviation.

62 65 65 57 65 55 59 58 59 69 58 68

The confidence interval estimate is

------- mi/h<< ------- mi/h.

(Round to one decimal place asneeded.)