Name: ______________________________________
AP Statistics
AP Review – Design #2
1. To survey the opinions of bleacher fans at Wrigley Field, a surveyor plans to select every
one-hundredth fan entering the bleachers one afternoon. Will this result in a simple rand
sample of Cub fans that sit in the bleachers?
a) Yes, because each bleacher fan has the same chance of being selected.
b) Yes, but only if there is a single entrance to the bleachers.
c) Yes, because the 99 out of 100 bleachers fans who are not selected will form a
control group.
d) Yes, because this is an example of systematic sampling, which is a special case of
SRS.
e) No, because not every sample of intended size has an equal chance of being
selected.
2. What fault do all these sampling designs have in common?
I.
The Wall Street Journal plans to make a prediction for a presidential election
based on a survey of its readers.
II. A radio talk show asks people to phone in their views on whether the United
States should pay off its huge debt to the United Nations.
III. A police detective, interested in determining the extent of drug use by
teenagers, randomly picks a sample of high school students and interviews each
one about any illegal drug use by the student during the past year.
a) All the designs make improper use of stratification.
b) All the designs have errors that can lead to strong bias.
c) All the designs confuse association with cause and effect.
d) None of the designs satisfactorily controls for sampling error.
e) None of the designs makes use of chance in selecting a sample.
3. To conduct a survey of long-distance calling patterns, a researchers opens a telephone
book to a random page, closes his eyes, puts his finger down on the page, and then reads
off the next 50 names. Which of the following are true statements?
I.
The survey design incorporates chance.
II. The procedure results in a simple random sample.
III. The procedure could easily result in selection bias.
a) I and II
d) I, II, and III
b) I and III
e) None of the above gives the
c) II and III
complete set of true responses.
4. Which of the following are important in the design of experiments?
I.
Control of confounding variables.
II.
Randomization in assigning subjects to different treatments
III. Replication of the experiment using sufficient numbers of subjects
a) I and II
d) I, II, and III
b) I and III
e) None of the above gives the
c)
II and III
complete set of true responses.
5. Some researchers believe that too much iron in the blood can raise the level of
cholesterol. Making periodic blood donations can lower the iron level in the blood. A study
is performed by randomly selecting half a group of volunteers to five periodic blood
donations while the rest do not. Is this an experiment or an observational study?
a) An experiment with control group and blinding.
b) An experiment with blocking
c) An observational study with comparison and randomization
d) An observational study with little bias
e) None of the above.
6. When the estrogen-blocking drug tamoxifen was first introduced to treat breast
cancer, there was concern that it would cause osteoporosis as a side effect. To test this
concern, half of the cancer volunteers were randomly selected and given tamoxifen, and
the remaining took a current cancer medication. Their bone density was measured before
and after treatment. Which of the following is a true statement?
I. This study was an observational study.
II. This study was a sample survey of randomly selected cancer patients.
III. This was an experiment in which the subjects were used as their own controls.
a) I only
b) II only
c) III only
d) I and II
e) None of the above gives the complete set of true responses.
7. A newspaper reporter examined police reports of accidents during the past 12 months to
collect data about the speed of a car and its stopping distance. The reporter then
constructed a scatter plot and computed a correlation coefficient to show the relation
between a car’s speed and its stopping distance. This is an example of
a) a double blind experiment
d) an observational study
b) a single blind experiment
e) a matched-pairs experiment
c) a experiment involving no blinding at all
8. A firm tested the durability of four different types of tires by having 4 Cadillacs each
randomly equipped with one of the types of tires. In similar fashion, 4 Fords were used,
each randomly equipped with one of the tire types. In a like manner, 4 Volkswagens were
each randomly outfitted with one of the four tire brands. Then each of the twelve cars
ran over a test track until the tires showed signs of serious wear. At that point the
average mileage of the three cars using one type of tire was compared to the average
mileage of the three cars using the second type of tires, and so on. This design is:
a) an example of randomized block design
b) an example of completely randomized
c) biased in favor of the first tire type
d) an example of an observational study
e) this is a random sample not an experiment
9. In the previous problem,
a) the type of car is the block
b) the type of tire is the factor
c) there are no blocks, it is random
d) none of the above
e) A and B
10. For which of the following purposes would it be most unreasonable to use a census?
a) To determine the proportion of students with a learning disability in a small rural
high school
b) To determine the proportion of red snappers with a high mercury level in the
Gulf of Mexico
c) To determine the difference between the proportion of engineering professors
and the proportion of business professor in favor of new teaching initiatives at a
large university
d) To determine the mean wage earned by construction workers in a small town
e) To determine the mean selling price of houses in your neighborhood
11. A company with offices in five different countries is interested in estimating the
proportion of its employees in favor of banning smoking on the office premises. It is known
that the views of people from different countries on issues like smoking tend to vary due
to the influence of different social structures. Which of the following is an appropriate
sampling technique to use in this situation, and why?
a) Stratified sample, because the population is divided into five strata – namely the
five offices in the five different countries
b) Stratified sample, because people in different countries use different languages
and thus will not be able to communicate to each other
c) Simple random sample, because the study has not been attempted before
d) Simple random sample, because this is the only method that gives unbiased
results
e) Simple random sample. Because this is the only method for which inferential
techniques are available
12. A large city was interested in annexing part of the surrounding county. In a survey
conducted by the local newspaper, 58% of respondents said they were against the
annexation. During the actual vote, not all eligible voters voted, but 56% of the
respondents voted against the annexation. Which of the following best describes the
difference in the percentages obtained from the newspaper poll and the vote itself?
a) It is an example of non-response bias, the systematic tendency of individuals
with particular characteristics to refuse to answer a survey question.
b) It is the systematic difference between a statistics and parameter caused by
the non-random selection of surveyed persons.
c) It is the difference between the same statistics computed from two different
samples.
d) It is the difference between the statistic and the truth due to use of a random
sample
e) It was caused by the large number of newspaper subscribers in the county.
13. In a clinical trial, 30 sickle-cell patients are randomly assigned to two groups. One
group receives the currently marketed medicine, and the other group receives the
experimental medicine. Each week patients report to the clinic where blood tests are
conducted. The lab technician is also unaware of the kind of medicine the patient is taking.
This design can be described as
a) a completely randomized design with two treatment groups, current medication
and the experimental medication
b) a matched-pairs design with the current medication and the experimental
medication forming a pair
c) a randomized block design with the current medication and the experimental
medication as two blocks
d) a randomized block design with the current medication and the experimental
medication as two treatments
e) a stratified design with two strata, patients with sickle-cell and those without
sickle-cell
14. Using the information in question 13, which of the following statements is true?
a) This is an example of a single blind design.
b) The explanatory variable is the amount of healthy blood cells in the blood.
c) The lab technician is the experimental unit
d) This is an example of a double-blind design.
e) There are two factors in this study.
15. An experiment was designed to test the effects of 3 different types of paint on the
durability of wooden toys. Since boys and girls tend to play differently with toys, a
randomly selected group of children was divided into 2 groups by gender. Which of the
following statements about this experiment is true?
a) There are 2 factors, types of paint and gender groups, giving a total of 6
treatment combinations
b) The type of paint is a blocking factor
c) Gender is a blocking factor
d) This is a completely randomized design
e) This is a matched-pairs design in which one boy and one girl are matched by age
to form a pair.
AP Review – Design #2
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