Probability Distribution: Auto Leases Consumer Banker Association released a report showing the lengths of automobile leases for new automobiles. The results are as follows.

Lease Length in Months Percent of Leases 13–24 12.7%

25–36 37.1%

37–48 28.5%

49–60 21.5%

More than 60 0.2%

(a) Use the midpoint of each class, and call the midpoint of the last class 66.5 months, for purposes of computing the expected lease term. Also fi nd the standard deviation of the distribution.

(b) Sketch a graph of the probability distribution for the duration of new auto leases.