We are interested in estimating, the mean length of time, in minutes, that workers in Chicago spend commuting to their jobs. A sample of 850 individuals was taken and their commute times were recorded. A 95%t-confidence interval forcomputed from these measurements is[20.55,23.21].

(a) Using the interval, compute x_bar, the observed sample mean commute time.(b) Using the interval, computes, the observed sample standard deviation.