, TESTBANK for Mind on Statistics , 6th Edition
Jessica M. Utts
Notes
1- The file is chapter after chapter.
2- We have shown you 10 or five pages.
3- The file contains all Appendix and Excel
sheet if it exists.
4- We have all what you need, we make
update at every time. There are many
new editions waiting you.
5- If you think you purchased the wrong file
You can contact us at every time, we can
replace it with true one.
Our email:
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Ch 1 - Statistics Success Stories
Exhibit 1-1
Suppose you were to read about a study showing that people who sleep less than five hours a night have
twice as much risk of a premature death as people who sleep seven or eight hours a night.
1. Refer to Exhibit 1-1. Can you conclude that sleeping the shorter hours causes a higher risk of
premature death?
a. No, because the result was clearly based on an observational study.
b. Yes, because the result was clearly based on a randomized experiment.
c. The answer depends on whether the research was based on an observational study or a
randomized experiment, and it isn't obvious which was used.
d. No, because the baseline risk of premature death is not given.
ANSWER: a
2. Refer to Exhibit 1-1. The "baseline risk" in this context is
a. the risk of premature death for people who sleep less than five hours a night.
b. the risk of premature death for people who sleep seven or eight hours a night.
c. the risk of premature death for all people.
d. the risk of premature death at the beginning of the study for those in the study.
ANSWER: b
3. Refer to Exhibit 1-1. Which of the following is not an example of a possible "confounding variable" in
this study?
a. Medications a person is taking.
b. The amount of alcohol a person drinks in the evening.
c. The amount of stress a person is under in their work.
d. The amount of sleep a person gets per night.
ANSWER: d
Exhibit 1-2
A randomized experiment was done by randomly assigning each participant either to walk for half an
hour three times a week or to sit quietly reading a book for half an hour three times a week. At the end of
a year the change in participants' blood pressure over the year was measured, and the change was
compared for the two groups.
4. Refer to Exhibit 1-2. This is a randomized experiment rather than an observational study because
a. blood pressure was measured at the beginning and end of the study.
b. the two groups were compared at the end of the study.
c. the participants were randomly assigned to either walk or read, rather than choosing their own
activity.
ANSWER: c
5. Refer to Exhibit 1-2. The two treatments in this study were
a. walking for half an hour three times a week and reading a book for half an hour three times a
week.
b. having blood pressure measured at the beginning of the study and having blood pressure
measured at the end of the study.
c. walking or reading a book for half an hour three times a week and having blood pressure
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Ch 1 - Statistics Success Stories
measured.
d. walking or reading a book for half an hour three times a week and doing nothing.
ANSWER: a
6. Refer to Exhibit 1-2. If a statistically significant difference in blood pressure change at the end of a
year for the two activities was found, then
a. it cannot be concluded that the difference in activity caused a difference in the change in
blood pressure because in the course of a year there are lots of possible confounding variables.
b. whether or not the difference was caused by the difference in activity depends on what else
the participants did during the year.
c. it cannot be concluded that the difference in activity caused a difference in the change in
blood pressure because it might be the opposite, that people with high blood pressure were
more likely to read a book than to walk.
d. it can be concluded that the difference in activity caused a difference in the change in blood
pressure.
ANSWER: d
7. Which of the following is not a component of "Statistics" as defined in Chapter 1?
a. Procedures and principles for gathering data
b. Procedures and principles for making decisions when faced with uncertainty
c. Procedures and principles for analyzing data and information
d. Procedures and principles for turning uncertainty into certainty
ANSWER: d
8. Which of the following is true about a dotplot and a five-number summary?
a. A dotplot displays all of the individual responses while a five-number summary does not.
b. A five-number summary displays all of the individual responses while a dotplot does not.
c. Both a dotplot and a five-number summary display all of the individual responses.
d. Neither a dotplot nor a five-number summary displays all of the individual responses.
ANSWER: a
9. The five numbers in a five-number summary are the
a. lowest value, mean, median, mode, and the highest value.
b. lowest value, lower margin of error, median, upper margin of error, and the highest value.
c. lowest value, lower quartile, median, upper quartile, and the highest value.
d. lowest value, 2nd lowest value, middle value, 2nd highest value, and the highest value.
ANSWER: c
10. Student grade point averages (GPAs) are calculated by assigning a number to each letter grade earned,
with A = 4, B = 3, C = 2, D = 1 and F = 0, then finding the average. A student proposes using the median
of the numbers instead and calls this medGPA. A student has taken five courses (all an equal number of
credit hours) and the grades were A, A, F, B, A. The usual GPA for these grades is 3.0. Should the
student prefer using the median (medGPA)?
a. No, because medGPA is F = 0 for this student.
b. It doesn't matter, because medGPA is also B = 3.0 for this student.
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Ch 1 - Statistics Success Stories
c. Yes, because medGPA is A = 4.0 for this student.
d. No, because if the student takes one more course and gets an A or B, the usual GPA will go up
but the medGPA will stay the same.
ANSWER: c
11. A pop quiz in a class resulted in the following eight quiz scores: 0, 60, 66, 78, 82, 96, 98, 100. The
five-number summary for these test scores is
a. 0, 63, 80, 97, 100.
b. 66, 78, 82, 96, 98.
c. 0, 66, 82, 98, 100.
d. 0, 25, 50, 75, 100.
ANSWER: a
12. Which of the following is true about the use of sample surveys?
a. Everyone in the population must also be in the sample.
b. Data from people in the sample are used to gain information about the population.
c. Data from people in the population are used to gain information about the sample.
d. The population is a subset of the sample.
ANSWER: b
13. Which of the following is true about the margin of error for the most common types of surveys?
a. If the number of individuals in the sample were to be substantially increased, the margin of
error would decrease.
b. If the number of individuals in the sample were to be substantially decreased, the margin of
error would also decrease.
c. If the number of individuals in the sample were to be substantially increased, the margin of
error would not change.
d. If the number of individuals in the sample were to be substantially decreased, the margin of
error would not change.
ANSWER: a
14. Suppose a Gallup Poll using a sample of 400 individuals found that 25% of them supported a
particular opinion. An interval that is 95% certain to contain the truth about the population percent who
support that opinion is
a. 25% ± 0.05% or 24.95% to 25.05%.
b. 25% ± 0.25% or 24.75% to 25.25%.
c. 25% ± 5% or 20% to 30%.
d. 25% ± 20% or 5% to 45%.
ANSWER: c
15. If a magazine sends a survey to a random sample of 10,000 of its subscribers but only 3000 of them
return the survey, the sample results may not be representative of the population of subscribers because
a. they used a self-selected sample.
b. there is likely to be nonresponse bias.
c. a volunteer sample was used.
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Ch 1 - Statistics Success Stories
d. they used a random sample.
ANSWER: b
16. In the study described in Case Study 1.4, questionnaires were sent to 100,000 women asking about
love, sex and relationships. Only 4.5% of the women responded. This means that
a. the margin of error for the survey was 4.5%.
b. a random sample was not contacted.
c. women who felt strongly did not respond.
d. nonresponse bias was likely to be a major problem.
ANSWER: d
17. "Does Prayer Lower Blood Pressure" was a question asked in Case Study 1.5. The moral of the story
was
a. cause-and-effect conclusions can generally be made in an observational study.
b. cause-and-effect conclusions cannot generally be made in an observational study.
c. cause-and-effect conclusions can generally be made in an experiment.
d. cause-and-effect conclusions cannot generally be made in an experiment.
ANSWER: b
18. If a difference seen in sample results is "statistically significant" it means that
a. there is an important difference in the sample results.
b. there is an important difference in the population.
c. the difference observed in the sample was unlikely to have occurred if there is no difference in
the population.
d. there is an important difference in the population that wasn't reflected in the sample results.
ANSWER: c
19. An organization would like to conduct a survey of a sample of their membership to make conclusions
about the entire membership. Given that they have a limited budget, they should focus their attention on
a. getting as large a sample as possible, even if they are all volunteers.
b. getting as large a sample as possible, even if they are not representative.
c. getting a representative sample.
d. getting a self-selected sample.
ANSWER: c
20. One of the common elements of the eight case studies in Chapter 1 is
a. in each case, a randomized experiment is described.
b. in each case, an observational study is described.
c. in each case, confounding variables are a problem.
d. in each case, data are used to make a judgment about the situation.
ANSWER: d
Exhibit 1-3
The result of an Internet poll was reported as evidence that most people believe the pledge of allegiance is
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Ch 1 - Statistics Success Stories
constitutional. The poll was conducted by posting a notice on a website and asking people to respond. The
results were based on 235 people who responded. Of the 235 people, 172 (73%) believed that the pledge
is constitutional, while 63 (27%) believed that the pledge is unconstitutional.
21. Refer to Exhibit 1-3. The results of this poll
a. are convincing, because 73% is an overwhelming majority.
b. are unreliable, because the sample size was too small.
c. are reliable, because the sample size was large enough.
d. cannot be generalized, because the results are based on a self-selected sample.
ANSWER: d
22. Refer to Exhibit 1-3. Assuming the poll had been based on a random sample with a sample size of
235, the reported margin of error of 3%
a. was correct.
b. was incorrect; the margin of error should be less than 1.0%.
c. was incorrect; the margin of error should be about 6.5%.
d. was incorrect; the margin of error should be about 3.5%.
ANSWER: c
23. A newspaper reported that 41% of students who had taken calculus in high school had a college
freshman year GPA (grade point average) of 3.2 or higher. The headline was "High School Courses Key
to College Grades". One potential problem with this headline is
a. motivated students could have both taken calculus in high school and have a high GPA (3.2 or
higher) in their freshman year in college.
b. the margin of error was not reported in the article, so the figure 41% may be very uncertain.
c. not all students with a freshman GPA of 3.2 or higher had taken calculus.
d. not all students who had taken calculus in high school had a freshman GPA of 3.2 or higher.
ANSWER: a
24. To investigate how trans fat consumption might affect fertility, researchers analyzed data available
from 18,555 healthy women who participated in the Nurses' Health Study between 1991 and 1999. All
were married and trying to get pregnant. It was reported that for every 2 percent increase in the amount of
calories a woman got from trans fats instead of carbohydrates, her risk of infertility increased by 73
percent.
Is the following statement true or false?
"Even though this was an observational study, a cause and effect relationship between the consumption of
trans fat and fertility has been established because the increase in risk is significantly more than 50
percent."
a. True
b. False
ANSWER: b
25. To investigate how trans fat consumption might affect fertility, researchers analyzed data available
from 18,555 healthy women who participated in the Nurses' Health Study between 1991 and 1999. All
were married and trying to get pregnant. It was reported that for every 2 percent increase in the amount of
calories a woman got from trans fats instead of carbohydrates, her risk of infertility increased by 73
percent.
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Ch 1 - Statistics Success Stories
Is the following statement true or false?
"The relationship between the consumption of trans fat and fertility may not be there at all, since it could
all be affected by a confounding variable such as exercise or environmental variables."
a. True
b. False
ANSWER: a
26. A news article with the headline "Arming commercial pilots" reported that 50% of first class and
business travelers believe that pilots should be armed as an additional security measure, while 50%
believed that pilots should not be armed. The results of the study
a. show that the American public was evenly divided on whether pilots should be armed or not.
b. does not show anything about the opinion of the American public because the sample was not
representative of the general public.
c. show that security was a concern for the American public.
d. does not show that security was a concern for the American public.
ANSWER: b
27. In a study of advanced colorectal cancer, 100 patients were randomly assigned to receive either a high
dose of Vitamin C or placebo. The study concluded that Vitamin C was not effective in the treatment of
advanced colorectal cancer because none of the patients with disease showed any improvement in the two
groups. The cause and effect conclusion
a. might be justified because randomization was used.
b. cannot be justified because anecdotal evidence from other patients not in the study, shows that
some people who take Vitamin C do recover from their disease.
c. cannot be justified because there could have been other systematic differences between the
two treatment groups, such as age and gender, so that the two groups cannot be compared to
each other.
d. could be justified because the sample size was fairly large (100 patients).
ANSWER: a
Exhibit 1-4
In a study of patients who had a heart attack, 3630 patients were randomly assigned to receive one of
three treatments: aspirin alone, warfarin alone, or aspirin plus warfarin. The results showed that 20.0% of
the aspirin group had another heart attack, stroke, or died, compared with 16.7% of the warfarin group
and 15.0% of the aspirin plus warfarin group. The difference between the aspirin and warfarin groups was
statistically significant, while the difference between the warfarin and aspirin plus warfarin group was not
statistically significant.
28. Refer to Exhibit 1-4. The statistically significant difference between the aspirin group (20.0%) and the
warfarin group (16.7%) means that
a. the difference between the two rates, 20.0% and 16.7%, is unlikely to have resulted from two
groups whose true rates of heart attack, stroke, or death were identical.
b. the difference between the two rates, 20.0% and 16.7%, is likely to have resulted from two
groups whose true rates were identical.
c. the difference between the two rates, 20.0% and 16.7%, is likely to have resulted from the
difference in sample sizes between the two groups.
d. the difference in the two rates, 20.0% and 16.7%, is likely to have resulted from other factors,
such as age and gender, on which the two groups differed.
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ANSWER: a
29. Refer to Exhibit 1-4. The non-statistically significant difference between the warfarin alone group
(16.7%) and the aspirin plus warfarin group (15.0%) means that
a. the difference between the two rates, 16.7% and 15.0%, is not medically important.
b. the difference between the two rates, 16.7% and 15.0%, is medically important.
c. the difference between the two rates, 16.7% and 15.0%, is unlikely to have resulted from two
groups whose true rates were identical.
d. the difference between the two rates, 16.7% and 15.0%, may have occurred by chance
between two groups whose true rates were identical.
ANSWER: d
30. An Islamic survey conducted by the Gallup organization consisted of a random sample of 10,004
people living in 9 predominantly Islamic countries. The sample was collected by interviewers going to
people's homes in randomly chosen areas in each of the 9 countries. The population represented by this
sample was
a. all Muslims in the world.
b. all Muslims who live in any Islamic country.
c. all people, Muslim and non-Muslim, living in homes in any of the 9 countries.
d. all people, Muslim and non-Muslim, who live in the same cities and villages as the people in
the sample.
ANSWER: c
31. A random sample of 1,002 adults aged at least 18 years and living in the 48 contiguous states (i.e. any
state in the United States excluding Alaska and Hawaii) was conducted by the Gallup Organization. The
interviews were done over the telephone. The population represented by this sample was
a. all adult Americans in the 48 contiguous states living in a household with a phone.
b. all adult Americans living in the same cities as people who were actually sampled.
c. all adult Americans.
d. all Americans.
ANSWER: a
32. If the sample size for a poll increases from 100 people to 400 people, the margin of error
a. increases by a factor of 4, i.e. is multiplied by 4.
b. increases by a factor of 2, i.e. is multiplied by 2.
c. decreases by a factor of , i.e. is multiplied by .
d. decreases by a factor of , i.e. is multiplied by .
ANSWER: c
33. According to the CIRP Freshman Survey, UCLA's annual survey of the nation's entering students at
four-year colleges and universities, conducted in 2010, female students were far less likely to report high
levels of emotional health than male students (45.9 percent versus 59.1 percent), a 13.2 percentage-point
difference. This difference was reported as statistically significant. The statistically significant difference
between male and female students means that
a. the difference between the two rates (45.9 percent versus 59.1 percent) is likely to have
resulted from two groups whose true rates of high levels of emotional health were identical.
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Ch 1 - Statistics Success Stories
b. the difference between the two rates (45.9 percent versus 59.1 percent) is unlikely to have
resulted from two groups whose true rates of high levels of emotional health were identical.
c. the difference between the two rates (45.9 percent versus 59.1 percent) is likely to have
resulted from the difference in sample sizes between male and female students.
d. the difference in the two rates (45.9 percent versus 59.1 percent) is likely to have resulted
from other factors, such as age and major, on which the two groups differed.
ANSWER: b
Exhibit 1-5
A five number summary for hours studied in a week were 5, 12, 14, 18, and 20.
34. Refer to Exhibit 1-5. What is the value such that 50% or more of the students studied longer than that
value?
a. 5 hours
b. 12 hours
c. 14 hours
d. 18 hours
ANSWER: c
35. Refer to Exhibit 1-5. What was the longest number of hours studied by anyone?
a. 12 hours
b. 14 hours
c. 18 hours
d. 20 hours
ANSWER: d
36. Refer to Exhibit 1-5. What was the shortest number of hours studied by anyone?
a. 5 hours
b. 12 hours
c. 14 hours
d. 18 hours
ANSWER: a
37. Refer to Exhibit 1-5. What is the value such that 75% or more of the students studied longer than that
value?
a. 5 hours
b. 12 hours
c. 14 hours
d. 18 hours
ANSWER: b
38. Refer to Exhibit 1-5. What is the value such that 25% or more of the students studied longer than that
value?
a. 5 hours
b. 12 hours
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Jessica M. Utts
Notes
1- The file is chapter after chapter.
2- We have shown you 10 or five pages.
3- The file contains all Appendix and Excel
sheet if it exists.
4- We have all what you need, we make
update at every time. There are many
new editions waiting you.
5- If you think you purchased the wrong file
You can contact us at every time, we can
replace it with true one.
Our email:
,Name: Class: Date:
Ch 1 - Statistics Success Stories
Exhibit 1-1
Suppose you were to read about a study showing that people who sleep less than five hours a night have
twice as much risk of a premature death as people who sleep seven or eight hours a night.
1. Refer to Exhibit 1-1. Can you conclude that sleeping the shorter hours causes a higher risk of
premature death?
a. No, because the result was clearly based on an observational study.
b. Yes, because the result was clearly based on a randomized experiment.
c. The answer depends on whether the research was based on an observational study or a
randomized experiment, and it isn't obvious which was used.
d. No, because the baseline risk of premature death is not given.
ANSWER: a
2. Refer to Exhibit 1-1. The "baseline risk" in this context is
a. the risk of premature death for people who sleep less than five hours a night.
b. the risk of premature death for people who sleep seven or eight hours a night.
c. the risk of premature death for all people.
d. the risk of premature death at the beginning of the study for those in the study.
ANSWER: b
3. Refer to Exhibit 1-1. Which of the following is not an example of a possible "confounding variable" in
this study?
a. Medications a person is taking.
b. The amount of alcohol a person drinks in the evening.
c. The amount of stress a person is under in their work.
d. The amount of sleep a person gets per night.
ANSWER: d
Exhibit 1-2
A randomized experiment was done by randomly assigning each participant either to walk for half an
hour three times a week or to sit quietly reading a book for half an hour three times a week. At the end of
a year the change in participants' blood pressure over the year was measured, and the change was
compared for the two groups.
4. Refer to Exhibit 1-2. This is a randomized experiment rather than an observational study because
a. blood pressure was measured at the beginning and end of the study.
b. the two groups were compared at the end of the study.
c. the participants were randomly assigned to either walk or read, rather than choosing their own
activity.
ANSWER: c
5. Refer to Exhibit 1-2. The two treatments in this study were
a. walking for half an hour three times a week and reading a book for half an hour three times a
week.
b. having blood pressure measured at the beginning of the study and having blood pressure
measured at the end of the study.
c. walking or reading a book for half an hour three times a week and having blood pressure
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Ch 1 - Statistics Success Stories
measured.
d. walking or reading a book for half an hour three times a week and doing nothing.
ANSWER: a
6. Refer to Exhibit 1-2. If a statistically significant difference in blood pressure change at the end of a
year for the two activities was found, then
a. it cannot be concluded that the difference in activity caused a difference in the change in
blood pressure because in the course of a year there are lots of possible confounding variables.
b. whether or not the difference was caused by the difference in activity depends on what else
the participants did during the year.
c. it cannot be concluded that the difference in activity caused a difference in the change in
blood pressure because it might be the opposite, that people with high blood pressure were
more likely to read a book than to walk.
d. it can be concluded that the difference in activity caused a difference in the change in blood
pressure.
ANSWER: d
7. Which of the following is not a component of "Statistics" as defined in Chapter 1?
a. Procedures and principles for gathering data
b. Procedures and principles for making decisions when faced with uncertainty
c. Procedures and principles for analyzing data and information
d. Procedures and principles for turning uncertainty into certainty
ANSWER: d
8. Which of the following is true about a dotplot and a five-number summary?
a. A dotplot displays all of the individual responses while a five-number summary does not.
b. A five-number summary displays all of the individual responses while a dotplot does not.
c. Both a dotplot and a five-number summary display all of the individual responses.
d. Neither a dotplot nor a five-number summary displays all of the individual responses.
ANSWER: a
9. The five numbers in a five-number summary are the
a. lowest value, mean, median, mode, and the highest value.
b. lowest value, lower margin of error, median, upper margin of error, and the highest value.
c. lowest value, lower quartile, median, upper quartile, and the highest value.
d. lowest value, 2nd lowest value, middle value, 2nd highest value, and the highest value.
ANSWER: c
10. Student grade point averages (GPAs) are calculated by assigning a number to each letter grade earned,
with A = 4, B = 3, C = 2, D = 1 and F = 0, then finding the average. A student proposes using the median
of the numbers instead and calls this medGPA. A student has taken five courses (all an equal number of
credit hours) and the grades were A, A, F, B, A. The usual GPA for these grades is 3.0. Should the
student prefer using the median (medGPA)?
a. No, because medGPA is F = 0 for this student.
b. It doesn't matter, because medGPA is also B = 3.0 for this student.
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Ch 1 - Statistics Success Stories
c. Yes, because medGPA is A = 4.0 for this student.
d. No, because if the student takes one more course and gets an A or B, the usual GPA will go up
but the medGPA will stay the same.
ANSWER: c
11. A pop quiz in a class resulted in the following eight quiz scores: 0, 60, 66, 78, 82, 96, 98, 100. The
five-number summary for these test scores is
a. 0, 63, 80, 97, 100.
b. 66, 78, 82, 96, 98.
c. 0, 66, 82, 98, 100.
d. 0, 25, 50, 75, 100.
ANSWER: a
12. Which of the following is true about the use of sample surveys?
a. Everyone in the population must also be in the sample.
b. Data from people in the sample are used to gain information about the population.
c. Data from people in the population are used to gain information about the sample.
d. The population is a subset of the sample.
ANSWER: b
13. Which of the following is true about the margin of error for the most common types of surveys?
a. If the number of individuals in the sample were to be substantially increased, the margin of
error would decrease.
b. If the number of individuals in the sample were to be substantially decreased, the margin of
error would also decrease.
c. If the number of individuals in the sample were to be substantially increased, the margin of
error would not change.
d. If the number of individuals in the sample were to be substantially decreased, the margin of
error would not change.
ANSWER: a
14. Suppose a Gallup Poll using a sample of 400 individuals found that 25% of them supported a
particular opinion. An interval that is 95% certain to contain the truth about the population percent who
support that opinion is
a. 25% ± 0.05% or 24.95% to 25.05%.
b. 25% ± 0.25% or 24.75% to 25.25%.
c. 25% ± 5% or 20% to 30%.
d. 25% ± 20% or 5% to 45%.
ANSWER: c
15. If a magazine sends a survey to a random sample of 10,000 of its subscribers but only 3000 of them
return the survey, the sample results may not be representative of the population of subscribers because
a. they used a self-selected sample.
b. there is likely to be nonresponse bias.
c. a volunteer sample was used.
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Ch 1 - Statistics Success Stories
d. they used a random sample.
ANSWER: b
16. In the study described in Case Study 1.4, questionnaires were sent to 100,000 women asking about
love, sex and relationships. Only 4.5% of the women responded. This means that
a. the margin of error for the survey was 4.5%.
b. a random sample was not contacted.
c. women who felt strongly did not respond.
d. nonresponse bias was likely to be a major problem.
ANSWER: d
17. "Does Prayer Lower Blood Pressure" was a question asked in Case Study 1.5. The moral of the story
was
a. cause-and-effect conclusions can generally be made in an observational study.
b. cause-and-effect conclusions cannot generally be made in an observational study.
c. cause-and-effect conclusions can generally be made in an experiment.
d. cause-and-effect conclusions cannot generally be made in an experiment.
ANSWER: b
18. If a difference seen in sample results is "statistically significant" it means that
a. there is an important difference in the sample results.
b. there is an important difference in the population.
c. the difference observed in the sample was unlikely to have occurred if there is no difference in
the population.
d. there is an important difference in the population that wasn't reflected in the sample results.
ANSWER: c
19. An organization would like to conduct a survey of a sample of their membership to make conclusions
about the entire membership. Given that they have a limited budget, they should focus their attention on
a. getting as large a sample as possible, even if they are all volunteers.
b. getting as large a sample as possible, even if they are not representative.
c. getting a representative sample.
d. getting a self-selected sample.
ANSWER: c
20. One of the common elements of the eight case studies in Chapter 1 is
a. in each case, a randomized experiment is described.
b. in each case, an observational study is described.
c. in each case, confounding variables are a problem.
d. in each case, data are used to make a judgment about the situation.
ANSWER: d
Exhibit 1-3
The result of an Internet poll was reported as evidence that most people believe the pledge of allegiance is
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constitutional. The poll was conducted by posting a notice on a website and asking people to respond. The
results were based on 235 people who responded. Of the 235 people, 172 (73%) believed that the pledge
is constitutional, while 63 (27%) believed that the pledge is unconstitutional.
21. Refer to Exhibit 1-3. The results of this poll
a. are convincing, because 73% is an overwhelming majority.
b. are unreliable, because the sample size was too small.
c. are reliable, because the sample size was large enough.
d. cannot be generalized, because the results are based on a self-selected sample.
ANSWER: d
22. Refer to Exhibit 1-3. Assuming the poll had been based on a random sample with a sample size of
235, the reported margin of error of 3%
a. was correct.
b. was incorrect; the margin of error should be less than 1.0%.
c. was incorrect; the margin of error should be about 6.5%.
d. was incorrect; the margin of error should be about 3.5%.
ANSWER: c
23. A newspaper reported that 41% of students who had taken calculus in high school had a college
freshman year GPA (grade point average) of 3.2 or higher. The headline was "High School Courses Key
to College Grades". One potential problem with this headline is
a. motivated students could have both taken calculus in high school and have a high GPA (3.2 or
higher) in their freshman year in college.
b. the margin of error was not reported in the article, so the figure 41% may be very uncertain.
c. not all students with a freshman GPA of 3.2 or higher had taken calculus.
d. not all students who had taken calculus in high school had a freshman GPA of 3.2 or higher.
ANSWER: a
24. To investigate how trans fat consumption might affect fertility, researchers analyzed data available
from 18,555 healthy women who participated in the Nurses' Health Study between 1991 and 1999. All
were married and trying to get pregnant. It was reported that for every 2 percent increase in the amount of
calories a woman got from trans fats instead of carbohydrates, her risk of infertility increased by 73
percent.
Is the following statement true or false?
"Even though this was an observational study, a cause and effect relationship between the consumption of
trans fat and fertility has been established because the increase in risk is significantly more than 50
percent."
a. True
b. False
ANSWER: b
25. To investigate how trans fat consumption might affect fertility, researchers analyzed data available
from 18,555 healthy women who participated in the Nurses' Health Study between 1991 and 1999. All
were married and trying to get pregnant. It was reported that for every 2 percent increase in the amount of
calories a woman got from trans fats instead of carbohydrates, her risk of infertility increased by 73
percent.
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Is the following statement true or false?
"The relationship between the consumption of trans fat and fertility may not be there at all, since it could
all be affected by a confounding variable such as exercise or environmental variables."
a. True
b. False
ANSWER: a
26. A news article with the headline "Arming commercial pilots" reported that 50% of first class and
business travelers believe that pilots should be armed as an additional security measure, while 50%
believed that pilots should not be armed. The results of the study
a. show that the American public was evenly divided on whether pilots should be armed or not.
b. does not show anything about the opinion of the American public because the sample was not
representative of the general public.
c. show that security was a concern for the American public.
d. does not show that security was a concern for the American public.
ANSWER: b
27. In a study of advanced colorectal cancer, 100 patients were randomly assigned to receive either a high
dose of Vitamin C or placebo. The study concluded that Vitamin C was not effective in the treatment of
advanced colorectal cancer because none of the patients with disease showed any improvement in the two
groups. The cause and effect conclusion
a. might be justified because randomization was used.
b. cannot be justified because anecdotal evidence from other patients not in the study, shows that
some people who take Vitamin C do recover from their disease.
c. cannot be justified because there could have been other systematic differences between the
two treatment groups, such as age and gender, so that the two groups cannot be compared to
each other.
d. could be justified because the sample size was fairly large (100 patients).
ANSWER: a
Exhibit 1-4
In a study of patients who had a heart attack, 3630 patients were randomly assigned to receive one of
three treatments: aspirin alone, warfarin alone, or aspirin plus warfarin. The results showed that 20.0% of
the aspirin group had another heart attack, stroke, or died, compared with 16.7% of the warfarin group
and 15.0% of the aspirin plus warfarin group. The difference between the aspirin and warfarin groups was
statistically significant, while the difference between the warfarin and aspirin plus warfarin group was not
statistically significant.
28. Refer to Exhibit 1-4. The statistically significant difference between the aspirin group (20.0%) and the
warfarin group (16.7%) means that
a. the difference between the two rates, 20.0% and 16.7%, is unlikely to have resulted from two
groups whose true rates of heart attack, stroke, or death were identical.
b. the difference between the two rates, 20.0% and 16.7%, is likely to have resulted from two
groups whose true rates were identical.
c. the difference between the two rates, 20.0% and 16.7%, is likely to have resulted from the
difference in sample sizes between the two groups.
d. the difference in the two rates, 20.0% and 16.7%, is likely to have resulted from other factors,
such as age and gender, on which the two groups differed.
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ANSWER: a
29. Refer to Exhibit 1-4. The non-statistically significant difference between the warfarin alone group
(16.7%) and the aspirin plus warfarin group (15.0%) means that
a. the difference between the two rates, 16.7% and 15.0%, is not medically important.
b. the difference between the two rates, 16.7% and 15.0%, is medically important.
c. the difference between the two rates, 16.7% and 15.0%, is unlikely to have resulted from two
groups whose true rates were identical.
d. the difference between the two rates, 16.7% and 15.0%, may have occurred by chance
between two groups whose true rates were identical.
ANSWER: d
30. An Islamic survey conducted by the Gallup organization consisted of a random sample of 10,004
people living in 9 predominantly Islamic countries. The sample was collected by interviewers going to
people's homes in randomly chosen areas in each of the 9 countries. The population represented by this
sample was
a. all Muslims in the world.
b. all Muslims who live in any Islamic country.
c. all people, Muslim and non-Muslim, living in homes in any of the 9 countries.
d. all people, Muslim and non-Muslim, who live in the same cities and villages as the people in
the sample.
ANSWER: c
31. A random sample of 1,002 adults aged at least 18 years and living in the 48 contiguous states (i.e. any
state in the United States excluding Alaska and Hawaii) was conducted by the Gallup Organization. The
interviews were done over the telephone. The population represented by this sample was
a. all adult Americans in the 48 contiguous states living in a household with a phone.
b. all adult Americans living in the same cities as people who were actually sampled.
c. all adult Americans.
d. all Americans.
ANSWER: a
32. If the sample size for a poll increases from 100 people to 400 people, the margin of error
a. increases by a factor of 4, i.e. is multiplied by 4.
b. increases by a factor of 2, i.e. is multiplied by 2.
c. decreases by a factor of , i.e. is multiplied by .
d. decreases by a factor of , i.e. is multiplied by .
ANSWER: c
33. According to the CIRP Freshman Survey, UCLA's annual survey of the nation's entering students at
four-year colleges and universities, conducted in 2010, female students were far less likely to report high
levels of emotional health than male students (45.9 percent versus 59.1 percent), a 13.2 percentage-point
difference. This difference was reported as statistically significant. The statistically significant difference
between male and female students means that
a. the difference between the two rates (45.9 percent versus 59.1 percent) is likely to have
resulted from two groups whose true rates of high levels of emotional health were identical.
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b. the difference between the two rates (45.9 percent versus 59.1 percent) is unlikely to have
resulted from two groups whose true rates of high levels of emotional health were identical.
c. the difference between the two rates (45.9 percent versus 59.1 percent) is likely to have
resulted from the difference in sample sizes between male and female students.
d. the difference in the two rates (45.9 percent versus 59.1 percent) is likely to have resulted
from other factors, such as age and major, on which the two groups differed.
ANSWER: b
Exhibit 1-5
A five number summary for hours studied in a week were 5, 12, 14, 18, and 20.
34. Refer to Exhibit 1-5. What is the value such that 50% or more of the students studied longer than that
value?
a. 5 hours
b. 12 hours
c. 14 hours
d. 18 hours
ANSWER: c
35. Refer to Exhibit 1-5. What was the longest number of hours studied by anyone?
a. 12 hours
b. 14 hours
c. 18 hours
d. 20 hours
ANSWER: d
36. Refer to Exhibit 1-5. What was the shortest number of hours studied by anyone?
a. 5 hours
b. 12 hours
c. 14 hours
d. 18 hours
ANSWER: a
37. Refer to Exhibit 1-5. What is the value such that 75% or more of the students studied longer than that
value?
a. 5 hours
b. 12 hours
c. 14 hours
d. 18 hours
ANSWER: b
38. Refer to Exhibit 1-5. What is the value such that 25% or more of the students studied longer than that
value?
a. 5 hours
b. 12 hours
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