Question

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 25-36 37-48 49-60 More than 60	14.8% 35.8% 28.9% 19.8% 0.7%

(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. (Round your answers to two decimal places.)

expected lease term	months
standard deviation

Answer 1

X P(x) x*P(x) x^2*P(x)

17.5 0.148 2.59 45.33

30.5 0.358 10.92 333.03

42.5 0.289 12.28 522.01

54.5 0.198 10.79 588.11

66.5 0.07 4.66 309.56

total 41.24 1798.03

mean 41.24

variance 97.50

standard dev 9.87

As,mean = sum of x*px

Variance = sum of x^2*px - mean^2

Standard deviation = sqrt( variance)

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