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Exam #1 (Chapters 1 - 6)
3
Please Show Work, when possible! (If you don't, I can't give you partial'credit!)
1. In June 2003 Consumer Reports published an article on some sport-utility vehicles they had tested
recently. They reported some basic information about each of the vehicles and the results of some tests
c o 9 t e d by their staff.
told the b&d
-and nage of each vehicle, its
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-1price and whe er it had
transmission. They reported the vehicle's fuel
economy (in m~lesper
of seconds to go from zero to 60 mph), and its
braking distance (in feet) to stop from 60 mph.
a) List the yar.iables and indicate whether each variable.-is categorical or quantitative. If the variable
is quantitative, state the units.
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b) Are any of the variables identifiers? If so, which one(s)?
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took a big test, and the highest score was 92. When the tests were
score
discovered a grading error. After correcting the error,
that student's score made each of these summary statistics
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ro determine if people's preference in dogs had changed in recent years, organizers of a local dog show
asked people who attended the show to indicate which breeds was their favorite. This information was
compiied by dog breed and gender of the people who responded. The table summarizes the responses.
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Do you think the breed selection is independent of gender? Give statistical evidence to support your
conclusion. Please explain clearly what statistics you are referring to and explain what these statistics
mean.
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4; The boxplots show prices of used cars (in thousands of dollars) advertised for sale at three local different
car dealers.
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a) Which dealer offers the cheapest car offered, and at what price? Explain for partial credit.
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b) Which dealer has the lowest median price, and how much is it? Explain for partial credit.
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c) Which dealer has the smallest price range, and what is it? Explain for partial credit.
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d) Which dealer's prices have the smalles IQR ,and what is it? Explain for partial credit.
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e, Which dealerpeneralll' sells cars cheapest? Explain for partial credit.
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5. The World Almanac and Book of Facts 2004 reported the percent of people not covered by health
for the year 2002. Computer output gives these
insurance in the 50 states and Washington, D.C.,
summaries for the percent
of people not covered bv.health insurance:
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Mean
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SD
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a) Were any of the states outliers? Explain how you made your decision.
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b) Is it mor~@~fo&iate'
to dse the mean and standard deviation OR the median and IQR to
describe these data? Explain, using the following histogram of the data:
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6.. Costs for standard veterinary services at a local animal hospital follow a Normal model with a mean
$80 and a standard deviation of $20.
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b) Is it usual to have a veterinary bill for $125? Explain.
C) ~'hat-i-s
the IQR for the costs.of btandard veterinary services? Show your work.
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7. A machine that fills cans with soda fills according to a Normal model with a mean of 12.1 ounces and a
standard deviation of 0.05 ounces.
a) If the cans claim to have 12 ounces of soda each, what percent pf cans are under-filled?
(meaning, on the can it is printed that there is 12 ounces of soda) Show work for partial credit!
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b) Management wants to ensure that.only 1% of cans are under-filled. If the meai"fil1of the &ins
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remains at 12.1 ounces, what standard deviation does the filling machbie need to have to achieve
this goal? Show work for partid credit!
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c) What does it mean to reduce the standard deviation, in this context?
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