Question

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

61 63 63 57 63 52 60 59 60 70 62 68

The confidence interval estimate is ------mi/h < σ <------ mi/h.
(Round to one decimal place as needed.)
Does the confidence interval describe the standard deviation for all times during the week? Choose the correct answer
below.
A. No. The confidence interval is an estimate of the standard deviation of the population of
speeds at 3:30 on a weekday, not other times.
B. Yes. The confidence interval describes the standard deviation for all times during the week.

Answer 1