Test 5A
AP Statistics
Name:
Directions: Work on these sheets. A random digit table is provided separately.
Part 1: Multiple Choice. Circle the letter corresponding to the best answer.
1. What do we call a sample that consists of the entire population?
(a) A stratum
(b) A multistage sample
(c) A mistake. A sample can never be the entire population.
(d) A census
(e) None of the above. The answer is _________________________.
2. A member of Congress wants to know what his constituents think of proposed legislation on
health insurance. His staff reports that 228 letters have been received on the subject, of which
193 oppose the legislation. What is the population in this situation?
(a) The constituents
(b) The 228 letters received
(c) The 193 opposing the legislation
(d) Congress
(e) None of the above. The answer is _____________________________.
3. Which of the following is a method for improving the accuracy of a sample?
(a) Use no more than 3 or 4 words in any question
(b) When possible, avoid the use of human interviewers, relying on computerized dialing
instead
(c) Use large sample sizes
(d) Use smaller sample sizes
(e) None of the above. The answer is _____________________________.
4. We say that the design of a study is biased if which of the following is true?
(a) A racial or sexual preference is suspected
(b) Random placebos have been used
(c) Certain outcomes are systematically favored
(d) The correlation is greater than 1 or less than 1
(e) None of the above. The answer is _____________________________.
5. Control groups are used in experiments in order to . . .
(a) Control the effects of lurking variables such as the placebo effect
(b) Control the subjects of a study so as to insure all participate equally
(c) Guarantee that someone other than the investigators, who have a vested interest in the
outcome, control how the experiment is conducted
(d) Achieve a proper and uniform level of randomization
(e) None of the above. The answer is ______________________________.
Chapter 5
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Test 5A
Part 2: Free Response
Answer completely, but be concise. Write sequentially and show all steps.
Suppose the Richmond-Times Dispatch asks a sample of 150 Richmonders their opinions on the
quality of life in Richmond.
6. Is this study an experiment? Explain why or why not.
7. Identify the sample and the population in the opinion poll in (6).
Read the brief article about aspirin and alcohol.
Aspirinmayenhanceimpairmentbyalcohol
Aspirin,alongtimeantidoteforthesideeffectsofdrinking,mayactuallyenhancealcoholseffect,
researchersattheBronxVeteransAffairsMedicalCentersay.
InareportonastudypublishedintheJournaloftheAmericanMedicalAssociation,theresearchers
saidtheyfoundthataspirinsignificantlyloweredthebodysabilitytobreakdownalcoholinthestomach.
Asaresult,fivevolunteerswhohadastandardbreakfastandtwoextrastrengthaspirintabletsanhour
beforedrinkinghadbloodalcohollevels30percenthigherthanwhentheydrankalcoholalone.Each
volunteerconsumedtheequivalentofaglassandahalfofwine.
That30percentcouldmakethedifferencebetweensobrietyandimpairment,saidDr.CharlesS.Lieber,
medicaldirectoroftheAlcoholResearchandTreatmentCenterattheBronxcenter,whowascoauthor
ofthereportwithDr.RistoRoine.
8. Does this article describe an experiment? Explain.
9. Did this study involve a simple random sample (SRS)? Explain.
10. Did this study use a particular design that we have studied? If so, identify the design. Then
comment on the validity of the study.
Chapter 5
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Test 5A
Bias is present in each of the following sampling designs. In each case, identify the type of bias
involved and state whether you think the sampling frequency obtained is lower or higher than the
actual population parameter.
11. A political pollster seeks information about the proportion of American adults that oppose gun
controls. He asks a SRS of 1000 American adults: "Do you agree or disagree with the
following statement: Americans should preserve their constitutional right to keep and bear
arms." A total of 910, or 91%, said "agree" (that is, 910 out of the 1000 oppose gun controls).
12. A flour company in Minneapolis wants to know what percentage of local households bake at
least twice a week. A company representative calls 500 households during the daytime and
finds that 50% of them bake at least twice a week.
It is believed that 75% of all apartment dwellers in a large city deadbolt their doors in addition to
locking them as an added precaution against burglary.
13. Describe (in words, and in detail) how you would simulate a SRS of 20 apartment dwellers.
14. Beginning at line 127 in the random digit table, actually simulate a SRS of 20 apartment
dwellers. (Reminder: Show Your Work!) What is the proportion p of people in the sample who
deadbolt their doors?
Chapter 5
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Test 5A
You are participating in the design of a medical experiment to investigate whether or not a calcium
supplement in the diet will reduce the blood pressure of middle-aged men. Preliminary research
suggests that the supplement may have a greater effect on black men than on white men.
15. What sort of experimental design would you choose, and why?
16. Assume that the experimental population consists of 600 white men and 500 black men.
Outline in a diagram the design of the experiment. (Be sure to indicate how many subjects are
assigned to the various treatment groups.)
17. Use Line 134 of the Random Number Table to select the first 5 whites for the study, and use
Line 142 to select the first 5 blacks for the study.
I pledge that I have neither given nor received aid on this test.
Chapter 5
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Test 5A
