Ws. Sampling/Observational/Experimental Design
AP STATS
Name_________________
Date______Per_____
1. A manufacturer of equipment for boats is interested in producing a new type of marine radio with an emergency
homing beacon. It is expensive to set up production, so the manufacturer wants to determine the level of interest
in purchasing such a device before money is invested in this venture. The company is located on the West
Coast, which is its primary market. The company decides to randomly select 12 of the marinas on the West
Coast and then demonstrate the prototype to all of the boat owners at these marinas and gauge the potential
market for the device. What sampling method did the company use to gather its data?
A)
B)
C)
D)
E)
Simple random sample
Systematic
Stratified
Cluster
Convenience
2. A national retail chain wants to test-market a new product line: bed and bath accessories created by a nationally
known clothing designer. The chain has approximately 1500 stores across the country. The locations of these
stores are downtown in urban cities, are in suburban shopping malls, or are stand-alone stores in medium-size
cities. The chain decides to randomly select 20 of its downtown stores, 20 of its suburban stores, and 20 of its
small-city stores in which to test the product line. What type of sampling method did the retail chain use?
A)
B)
C)
D)
E)
Simple random sample
Systematic
Stratified
Cluster
Convenience
3. A newspaper wants to determine the level of support in a large town regarding the construction of a new library
in a downtown location. Which one of the following would represent a stratified sampling method?
A)
B)
C)
D)
Randomly select four residential blocks in the town and ask everyone who lives on those blocks.
Select every fourth person who enters the current library until the desired numbers of people are selected.
Take an SRS of people from the city phone directory.
Take a random sample of residents from each of the northwest, northeast, southwest, and southeast
quadrants of the city.
E) Number the residents of the town using the latest census data. Use a random number generator to pick the
sample.
4. A public opinion poll in Ohio wants to determine whether registered voters in the state approve of a measure to
ban smoking in all public areas. They select a simple random sample of 50 registered voters from each county in
the state and ask whether they approve or disapprove of the measure. This is an example of
A) a systematic county sample.
D) a simple random sample.
B) a cluster sample.
E) a stratified sample.
C) a multistage sample.
5. A marketing research firm wishes to determine if the adult men in Laramie, Wyoming, would be interested in a
new upscale men’s clothing store. From a list of all residential addresses in Laramie, the firm selects a simple
random sample of 100 and mails a brief questionnaire to each. The population of interest is
A) all adult men in Laramie, Wyoming.
B) all residential addresses in Laramie, Wyoming.
C) the members of the marketing firm that actually conducted the survey.
D) the 100 addresses to which the survey was mailed.
E) the people who respond to the questionnaire.
6. In order to assess the opinion of students at the University of Minnesota on campus snow removal, a reporter
for the student newspaper interviews the first 12 students he meets who are willing to express their opinion. In
this case, the sample is
A) all those students favoring prompt snow removal.
B) all students at universities receiving substantial snow.
C) the 12 students interviewed.
D) the students attending school during the semester.
E) all students at the University of Minnesota.
7. In order to assess the opinion of students at the University of Minnesota on campus snow removal, a reporter for
the student newspaper interviews the first 12 students he meets who are willing to express their opinion. The
method of sampling used is
A) numerical sampling.
D) a census.
B) convenience sampling.
E) simple random sampling.
C) voluntary response.
8. A researcher wants to determine the mean income of adults in a particular state. She decides to take a random
sample of 1525 citizens with a driver’s license from the registry maintained by the Department of Motor
Vehicles in that state, and record their incomes. Which one of the following statements is NOT correct?
a.
b.
c.
d.
e.
People who had recently moved from another state may not yet be included in the DMV registry.
The sample would not be representative of adults, since teenagers would be included in the sample.
The sample would be biased since some people without a license may be too poor to own a car and
others may choose to use public transportation.
The distribution of incomes in the sample would probably be skewed to the right.
Taking a bigger sample from the registry would solve any problems with possible bias
9. Which statement below represents a major advantage of an experimental study relative to an observational
study?
a.
b.
c.
d.
e.
Experimental studies are usually less expensive to conduct.
Experimental data are more readily available.
You need fewer subjects in an experiment.
Experimental studies provide stronger evidence of cause-and-effect relationships.
Experimental studies rely on data from treatments, so it is easier to assess any limitations on the scope
of inference.
10. A music education specialist speaking on a local newscast has advocated that young children learn to play a
musical instrument. The author cited a study of 650 randomly selected high school sophomores and juniors,
which reported that students who play a musical instrument score, on average, 51 points higher on an
academic achievement test than students who do not play an instrument. Which one of the following is a
correct statement?
a.
b.
c.
d.
e.
Since playing a musical instrument seems to improve achievement scores for high school students, the
effect should be similar for younger children.
Playing a musical instrument will cause a student to score higher on the AP Statistics test.
The study was an experiment rather than an observational study.
The study was a matched-pair study.
There seems to be a relationship between playing a musical instrument and obtaining a higher score on
the achievement test.
11. Why would blocking be used in an experiment?
1.
a)
to increase randomizations
b) to increase sensitivity
d)
to reduce bias
e) to increase sample size
c) to reduce variation
12. Which of the following is NOT a characteristic of stratified random sampling?
2.
a)
Random sampling is part of the sampling procedure.
b)
The population is divided into groups of units that are similar on some characteristic.
c)
The strata are based on facts known before the sample is selected.
d)
Each individual unit in the population belongs to one and only one of the strata
e)
Every possible subset of the population, of the desired sample size, has an equal chance of being
selected.
13. Which is important in designing a good experiment?
3.
I. Randomization in assigning subjects to treatments.
II. Control of potentially confounding variables.
III. Replication of the experiment on a sufficient number of subjects.
a)
I only
b) I and II only
d)
II and III only
e) I, II, and III
c) I and III only
14.
4. Can watching a movie temporarily raise your pulse rate? Researchers have 50 volunteers check their pulse
rates. Then they watch an action film, after which they check their pulse rate once more. Which aspect of
experimentation is present in this research?
a)
A placebo
b) Blinding
d)
A control group
e) None of these
c) Randomization
15.
5. 20 dogs and 20 cats were subjects in an experiment to test the effectiveness of a new flea control chemical.
Ten of the dogs and 10 of the cats were randomly assigned to an experimental group that wore a collar
containing the chemical, while the others wore a similar collar without the chemical. After 30 days,
veterinarians were asked to inspect the animals for fleas and evidence of flea bites. This experiment is…
a)
Completely randomized with one factor: the type of collar
b)
Completely randomized with one factor: the species of animal
c)
Randomized block, blocked by species
d)
Randomized block, blocked by type of collar
e)
Completely randomized with two factors: the type of collar and species
16. In order to reduce survey costs, only residents living within a 5 mile radius are considered for a survey. What
type of sample design has been used?
a)
convenience sample
b)
voluntary response sample
c)
simple random sample
d)
e)
stratified sample
systematic sample
Answers: 1. D 2. C 3. D 4. E 5. B 6. C 7. B 8. E
9. D 10. E 11. D 12. E 13. E 14. E 15. C 16. A