AP Statistics Chapter 12-13 Review
Name:____________________
Multiple Choice: Choose the letter of the best choice.
__B _ 1.
A company sponsoring a new Internet search engine wants to collect data on the ease of using it.
Which is the best way to collect the data?
A) Census
B) Sample survey
C) Observational study
D) Experiment
E) None of these
__D__ 2.
The January 2005 Gallup Youth Survey telephoned a random sample of 1,028 U.S. teens aged 13-17
and asked these teens to name their favorite movie from 2004. Napoleon Dynamite had the highest
percentage with 8% of teens ranking it as their favorite movie.
Which is true?
I.
The population of interest is U.S. teens aged 13-17.
II.
8% is a statistic and not the actual percentage of all U.S. teens who would rank this
movie as their favorite.
III.
This is an example of a stratified random sample.
A) I only
B) II only
C) III only
D) I and II only
E) I, II, and III
__D__ 3.
Suppose a local school district decides to randomly test high school students for attention deficit
disorder (ADD). There are three high schools in the district, each with grades 9-12. The school
board pools all of the students together and randomly samples 250 students. What sampling method
was used?
A) Stratified random sample
B) Convenience sample
C) Cluster sample
D) SRS (simple random sample)
E) Systematic sample
__C__ 4.
More dogs are being diagnosed with thyroid problems than have been diagnosed in the past. A
researcher identified 50 puppies without thyroid problems and kept records of their diets for several
years to see if any developed thyroid problems. This is a(n):
A) Randomized experiment
B) Survey
C) Prospective study
D) Retrospective study
E) Blocked experiment
__A__ 5.
Which of the following is not required in an experimental design?
A) Blocking
B) Control
C) Randomization
D) Replication
E) All are required in an experimental design.
__D__ 6.
A chemistry professor who teaches a large lecture class surveys his students who attend his class
about how he can make the class more interesting, hoping he can get more students to attend. This
survey method suffers from which type of bias:
A) Voluntary response
B) Nonresponse
C) Response
D) Undercoverage
E) There is no bias present
__E__ 7.
Double-blinding in experiments is when:
I.
The evaluators do not know which treatment group the participants are in.
II.
The participants do not know which treatment group they are in.
III.
The treatment administrators don’t know which treatment group the participants are
in.
A) I only
B) II only
C) III only
D) II and III only
E) I, II, and III
__B__ 8.
Scientists examined the glycogen content of rats’ brains at the rats’ normal bedtimes and after they
had been kept awake for an extra 6, 12, or 24 hours. The scientists found that glycogen was 38%
lower among rats that had been sleep-deprived for 12 hours or more, and that the levels recovered
during subsequent sleep. These researchers speculated that we may need to sleep in order to restore
the brain’s energy fuel. (Science News, July 20, 2002) Which is true?
A) There is 1 factor with 3 levels
B) There is 1 factor with 4 levels
C) There are 3 factors with 1 level each
D) There are 4 factors with 1 level each
E) There are only 5 treatments
__D_ 9.
Placebos are a tool for:
A) Sampling
B) Blocking
C) Control
D) Blinding
E) Randomization
__A__10. In a group of 500 women, those who smoked moderately did worse on test of reaction time than those
who did not smoke. Identify the subjects studied.
A) Women who smoked moderately and women who did not smoke.
B) Women
C) Adults who smoked moderately and adults who did not smoke
D) Women who smoked moderately
E) Women who did not smoke.
11. Military funding A college group is investigating student opinions about funding of the military. They
phone a random sample of students at the college, asking each person the following question:
“Do you think that funding of the military should be increased so that the United States can better protect
its citizens?”
_____ Yes
____ Not
_____ No Opinion
a) Explain how bias may have been introduced on the way this sample of students was selected.
Non-Response bias, students selected may not answer the phone or choose not to give an opinion
b) Explain how bias may have been introduced on the way the question was worded. Describe and name the
bias.
Response bias, the “…United States can better protect its citizens” is leading to a “yes” vote.
c) Suggest how it could have been worded to avoid this bias.
EX. “Do you think that military funding should be increased?”
12. College students’ spending A consumer group wants to see if a new education program will improve the
spending habits of college students. Students in an economics class are randomly assigned to three different
courses on spending habits.
a) What are the experimental units?
_______Economics Class (students in )__________
b) How many factors are there?
________1________
c) How many levels are there?
________3________
d) How many treatments are there?
________3________
e) What is the response variable?
______Spending habits (improvement)__________
13. Tips In restaurants, servers rely on tips as a major source of income. Does serving candy after the meal
produce larger tips? To find out, two waiters determined randomly whether or not to give candy to 92 dining
parties. They recorded the sizes of the tips, and reported that guests getting candy tipped an average of 17.8% of
the bill, compared with an average of only 15.1% form those who got no candy. (Journal of Applied Social
psychology 32, no.2[2002]: 300-309)
a) Was this an experiment or an observational study?
Experiment
b) The researchers said the difference was statistically significant. Explain in this context what that
means.
There is a large enough difference in tips that could have not just happened by chance, but is a
result of the waiters serving candy.
14. Bone Builder Researchers believe that a new drug called Bone Builder will help bones heal after children
have broken or fractured a bone. The researchers believe that Bone Builder will work differently on bone breaks
than on bone fractures. Bone Builder will be used in conjunction with traditional casts. To test the impact of
Bone Builder on the bone healing, the researchers recruit 18 children with bone breaks and 30 children with bone
fractures, where half of each group is given Bone Builder and the other half is given a placebo.
a) Is this a “completely randomized” or “randomized block” design?
Randomized block
b) Draw the appropriate experiment design.
18
Children
(breaks)
Compare
Bone conditions
Group 2 – Placebo
(9 children)
Block
Group 1 – Bone Builder
(15 children)
30
Children
(fractures)
Random
48
Children
Random
Group 1 – Bone Builder
(9 children)
Compare
Bone conditions
Group 2 – Placebo
(15 children)
c) If we are only interested in if the new drug “Bone Builder” works why do researchers bother with a
control group? Explain why it is necessary to have a control groups.
Need a control group to have a baseline reading. Be able to compare the results of the Bone Builder to
those who did not take the drug.
d) Why are the control groups given a placebo?
So that neither treatment groups knows who is getting the Bone Builder drug. Each group is treated the
same. Use of blinding. Helps eliminates the placebo effect.