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AP Stats
Chap 1-6
Practice Test
Name __________________________________________ Pd __________
SECTION I
Number of Questions – 16
Percent of Total Grade – 50
Directions: Solve each of the following problems, using the available space (or extra paper) for
scratchwork. Decide which is the best of the choices given and place that letter on the ScanTron
sheet. No credit will be given for anything written on these pages for this part of the test. Do not
spend too much time on any one problem.
1. Which of the following variables about German Shepherds is most likely to be described by a Normal
model?
A. breed
B. age
C. weight
D. number of days housed at the SPCA
E. veterinary costs
2. The SPCA has kept these data records for the past 20 years. If they want to show the trend in the
number of dogs they have housed, what kind of plot should they make?
A. boxplot
B. timeplot
C. bar graph
D. pie chart
E. histogram
3. The veterinary bills for the dogs are summarized in the display shown. Estimate the IQR of these
expenses.
A.
B.
C.
D.
E.
$50
$75
$100
$150
$200
4. Last weekend police ticketed 18 men whose mean speed was 72 miles per hour, and 30 women going
an average of 64 mph. Overall, what was the mean speed of all the people ticketed?
A. 67 mph
B. 68 mph
C. 69 mph
D. none of these
E. It cannot be determined.
5. Which is true of the data shown in this histogram?
I. The distribution is skewed to the right.
II. The mean is probably smaller than the median.
III. We should use the median and IQR to summarize these data.
A.
B.
C.
D.
E.
I only
II only
III only
II and III only
I, II, and III
6. The best estimate of the standard deviation of the mens’
weights displayed in this dotplot is
A. 10
B. 15
C. 25
D. 35
E. 40
7. If we want to discuss any gaps and clusters in a data set, which of the following should not be chosen
to display the data set?
A. histogram
B. stem-and-leaf plot
C. boxplot
D. dotplot
E. any of these would work
8. Suppose a Normal model describes the number of pages printer ink cartridges last. If we keep track of
printed pages for the 47 printers at a company’s office, which must be true?
I. The page counts for those ink cartridges will be normally distributed.
II. The histogram for those page counts will be symmetric.
III. 95% of those page counts will be within 2 standard deviations of the mean.
A.
B.
C.
D.
E.
none
I only
II only
II and III
I, II, and III
9. Suppose that a Normal model describes the fuel economy (miles per gallon) for automobiles and that a
Saturn has a standardized score (z-score) of +2.2. This means that Saturns…
A. get 2.2 miles per gallon.
B. get 2.2 times the gas mileage of the average car.
C. get 2.2 mpg more than the average car.
D. have a standard deviation of 2.2 mpg.
E. achieve fuel economy that is 2.2 standard deviations better than the average car.
10. Which of the following is likely to have a mean that is smaller than the median?
A. The salaries of all National Football League players.
B. The scores of students (out of 100 points) on a very easy exam in which most get nearlyperfect scores but a few do very poorly.
C. The prices of homes in a large city.
D. The scores of students (out of 100 points) on a very difficult exam in which most get poor
scores but a few do very well.
E. Amounts awarded by civil court juries.
11. There are three children in a room, ages three, four, and five. If a four-year-old child enters the room,
the…
A. mean age will stay the same but the standard deviation will increase.
B. mean age will stay the same but the standard deviation will decrease.
C. mean age and standard deviation will stay the same.
D. mean age and standard deviation will increase.
E. mean age and standard deviation will decrease.
12. The Five-Number Summary for scores on a statistics exam is 11, 35, 61, 70, 79. In all, 380 students
took the test. About how many had scores between 35 and 61?
A. 26
B. 76
C. 95
D. 190
E. none of these
13. A Normal Density Curve has which of the following properties?
I. It is symmetric.
II. It has a peak centered above the mean.
III. The spread of the curve is proportional to its standard deviation.
A.
B.
C.
D.
E.
II only
I and III
III only
I, II, and III
none
14. The area under the Standard Normal Curve corresponding to -0.3 < z < 1.6 is
A. 0.3273
B. 0.4713
C. 0.5631
D. 0.9542
E. none
15. Which of the following summaries are changes by adding a constant to each data value?
I. the mean
II. the median
III. the standard deviation
A.
B.
C.
D.
E.
I only
III only
I and II
I and III
I, II, and II
16. The plot shown is a Normal probability plot for a set of data. The
data value is plotted on the x-axis, and the standardized value
is plotted on the y-axis. Which statement is true for this data set?
A.
B.
C.
D.
E.
The data are clearly Normally distributed.
The data are approximately Normally distributed.
The data are clearly skewed to the right.
The data are clearly skewed to the left.
There is insufficient information to determine the shape of the distribution.
SECTION II
Part A
Questions 17-24
Percent of Section II Grade – 75
Directions: Show all of your work. Indicate clearly the methods you use, because you will be
graded on the correctness of your methods as well as on the accuracy of your results and
explanations.
Cordless Phones.
In their October 2003 issue, Consumer Reports evaluated the price and performance of 23 models of
cordless phones. Computer output gives these summaries for the prices:
17. Were any of these prices outliers? Explain how you made your decision.
18. One of the manufacturers advertises a cordless phone “economy-priced at only $31.95.” Would you
consider that to be a very low price? Explain.
Exercising.
Owners of an exercise gym believe that a Normal model is useful in projecting the number of clients who
will exercise in their gym each week. They use a mean of 800 clients and a standard deviation of 90
clients.
19. Draw and clearly label this model.
20. What is the first quartile of the weekly number of clients? Show your work.
21. An owner of another gym reports that 5% of the time their gym has fewer than 450 clients, and 40%
of the time the gym has more than 1085 clients. What parameters should that owner use for his
Normal model?
Veterinary Costs.
Costs for standard veterinary services at a local animal hospital follow a Normal model with a mean of
$80 and a standard deviation of $20.
22. Is it unusual to have a veterinary bill for $125? Explain.
23. What is the IQR for the costs of standard veterinary services? Show your work.
Soda Cans.
A machine that fills cans with soda fills according to a Normal model with mean 12.1 ounces and a
standard deviation of 0.05 ounces.
24. If the cans claim to have 12 ounces of soda each, what percent of cans are under-filled? Show your
work.
SECTION II
Part B
Question 25
Percent of Section II Grade – 25
Directions: Show all of your work. Indicate clearly the methods you use, because you will be
graded on the correctness of your methods as well as on the accuracy of your results and
explanations.
Network Ratings.
The following table gives the Nielsen ratings for the top 50 prime-time television shows for the first half
of the 1994-95 viewing season. Each ratings point represents 954,000 households.
25. a. Make an appropriate triple-display of the shows by network. Use graph paper or Fathom software.
b. How does ABC compare with NBC in the race for high ratings? Give appropriate graphical and
numerical evidence to support your answer.