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Chapter 2 Practice Test 153

13. According to the truecar.com website, the asking (b) According to the truecar.com site, any asking price
prices for cars of a certain model are approximately between $34,772 and $36,225 for this car model is 13. (a) (i) z = 35,625 −35,987 =−0.60;
normally distributed with mean $35,987 and stan- considered “good” or “great.” What proportion of 607.5
dard deviation $607.50. 30 cars have “good” or “great” asking prices?
(a) The factory invoice price for this model is $35,625. (c) The manufacturer’s suggested retail price (MSRP) for the proportion of z-scores less than
About what percent of cars have asking prices below this car model is at the 98th percentile of the distribu- z = –0.60 is 0.2743.
factory invoice? tion of asking price. Find the MSRP.
(ii) Applet/normalcdf(lower:–10000, Practice Test
upper: 35625,mean: 35987,SD: 607.5) =
0.2756. About 27.6% of cars have asking
prices below factory invoice.
34,772 −35,987
(b) (i) z = =−2 and
607.5
36,225 −35,987
(C) 2021 BFW Publishers -- for review purposes only.
z = = 0.39; the
607.5
proportion of z-scores between =z –2
=
and = 0.39 is 0.6517–0.0228 0.6289.
z
(ii) Applet/normalcdf(lower: 34772,
upper: 36225,mean: 35987,SD: 607.5) =
0.6296. About 62.96% of cars have “good”
or “great” asking prices.
(c) (i) z = 2.05 gives the closest value to
0.98.
x − 35,987
2.05 =
607.5
x = $37,232.38
(ii) Applet/invNorm(area: 0.98,mean:
=
35987,SD: 607.5) 37,234.65. About
98% of cars of this model have a MSRP
of less than $37,234.65, so a car with
MSRP of $37,234.65 would be at the
98th percentile of the distribution.

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CHAPTER 2 • Practice Test 153

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