Understanding Basic Statistics 6th Edition by Charles Henry Brase,Corrinne Pellillo Brase

Exercise 42

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

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