Deck 4: Sample Surveys in the Real World

Question 1

Professional sample surveys use careful random samples, usually by randomly dialing telephone numbers, to come close to an SRS. But the results that a sample survey actually obtains may be strongly biased because

A) the typical sample size of 1000 or 1500 people is too small.
B) the margin of error is too large.
C) surveys report only what their sponsors want to hear.
D) many people refuse to respond to telephone surveys.

Answer 1

many people refuse to respond to telephone surveys.

Question 2

In order to gauge student opinion on his grading procedures, the professor divides the class into two groups: undergraduate students and graduate students. He then takes random samples from each group. This is an example of:

A) simple random sampling.
B) cluster sampling.
C) stratified random sampling.
D) sampling in stages.

Answer 2

stratified random sampling.

Question 3

You want to know the opinions of American school teachers about establishing a national test for high school graduation. You obtain a list of the members of the National Education Association (the largest teachers' union) and mail a questionnaire to 2500 teachers chosen at random from this list. In all, 1347 teachers return the questionnaire. The sampling frame is

A) the 1347 teachers who mail back the questionnaire.
B) the 2500 teachers to whom you mailed the questionnaire.
C) all members of the National Education Association.
D) all American school teachers.
E) all American school students.

Answer 3

all members of the National Education Association.

Question 4

A survey was sent to a simple random sample of college sophomores. The sample size was 200. When asked whether or not they liked Frank Sinatra's music, 40 of these students did not give any answer. This is an example of

A) a stratified sample.
B) a census.
C) bias.
D) the margin of error.
E) nonresponse.

Question 5

A pollster wants to ask a sample of undergraduates at State Tech how they feel about a proposal to build a new dorm in the place of the school's largest commuter parking lot. Opinions may differ depending on whether the student is a commuter or resident, so the pollster takes separate SRSs of commuters and resident students and combines them to form his sample. He used a:

A) simple random sampling.
B) cluster sampling.
C) stratified random sampling.
D) sampling in stages.

Question 6

To study the security protocols at a major airport, ten passengers were randomly selected from each flight leaving the airport on a particular day and questioned about the security efforts they experienced while at the airport. This is an example of

A) simple random sampling.
B) stratified sampling.
C) cluster sampling.
D) sampling in stages.

Question 7

In 2014 Scotland was considering independence from England, going so far as to take a referendum vote. One opinion poll taken at the time showed that 51 percent of Scots favored "independence." In another poll taken at that same time, only 34 percent favored being "separate" from England. The primary reason these results differed by so much is that:

A) samples will usually differ just by chance due to random sampling.
B) the wording of questions has a big effect on poll results.
C) more follow-up efforts reduced the nonresponse rate of the second poll.
D) the sample sizes are different, so the margins of error are different.

Question 8

Which of the following is a source of nonsampling error in a sample survey?

A) Voluntary response sampling
B) Using voter registration lists as the sampling frame
C) Variation due to chance in choosing a sample at random
D) Using 95% confidence
E) None of the above

Question 9

A report from the U.S. Department of Health and Human Services estimated that 10.2 percent of Americans in 2014 had used illicit drugs with a margin of error of ± 0.18 percent. Suppose that many of those asked about their behavior give an answer that isn't the truth because they fear that their answer will go to law enforcement officials.

A) This is a sampling error that causes bias.
B) This is a sampling error that increases variability.
C) This is a nonsampling error that causes bias.
D) This is a nonsampling error that increases variability.

Question 10

Professor Lilli Gans wishes to study the relationship between a person's zodiac sign and his or her political opinions. She obtains the birthdays of all 816 students enrolled in her Astrology 101 course. Then she uses a random digits table to choose 10 students from each of the twelve zodiac signs. For example, students born from March 21 until April 19 have the Aries zodiac sign, and Professor Gans chooses 10 Aries students at random. She uses a different part of the table of random digits to choose students having each sign. After obtaining her sample, Professor Gans has the selected students fill out a questionnaire.
Professor Gans has obtained a

A) simple random sample from her class.
B) systematic random sample from her class.
C) stratified random sample, where the strata are students with different political opinions.
D) stratified random sample, where the strata are students with different zodiac signs.

Question 11

Which of the following sources of error is included in the margin of error?

A) Chance variation in choosing a random sample
B) Errors in entering the data into the computer
C) Some of the subjects did not understand the questions
D) Voluntary response
E) All of the above

Question 12

Some common sources of nonsampling error in samples of human populations are

A) using voluntary response samples; some subjects lie.
B) some subjects lie; some subjects can't be contacted.
C) some subjects can't be contacted; drawing a sample from names in a telephone directory.
D) Both B and C are correct.
E) Answers A, B, and C are correct.

Question 13

Concerned about the sanitation training practices of its employees, a major fast-food restaurant chain randomly selected 40 of its restaurants nationwide. All employees at these 40 restaurants were tested for their knowledge of both the restaurant chain and local health code practices. This is an example of:

A) simple random sampling.
B) stratified sampling.
C) cluster sampling.
D) sampling in stages.

Question 14

A(n) __________ is a list of units from which a sample is chosen.

A) individual
B) population
C) sampling frame
D) treatment

Question 15

An overnight opinion poll calls randomly selected telephone numbers. This polling method misses all people without a phone. Which of the following types of errors is present in this situation?

A) processing
B) Nonsampling
C) sampling
D) nonresponse

Question 16

To obtain student opinions on a particular issue, students were identified by major, and five students were randomly selected from within each major to be interviewed. This is an example of

A) simple random sampling.
B) stratified sampling.
C) cluster sampling.
D) sampling in stages.

Question 17

Increasing the size of a probability sample

A) decreases the level of confidence.
B) increases the variability of a sample statistic.
C) decreases the variability of a sample statistic.
D) increases the variability in a population parameter.
E) decreases the variability in a population parameter.

Question 18

Professor Lilli Gans wishes to study the relationship between a person's zodiac sign and his or her political opinions. She obtains the birthdays of all 816 students enrolled in her Astrology 101 course. Then she uses a random digits table to choose 10 students from each of the twelve zodiac signs. For example, students born from March 21 until April 19 have the Aries zodiac sign, and Professor Gans chooses 10 Aries students at random. She uses a different part of the table of random digits to choose students having each sign. After obtaining her sample, Professor Gans has the selected students fill out a questionnaire.
One of the questions in Professor Gans's questionnaire asks whether the student has ever given money to the American Nazi Party. Any students who have done so are likely to lie and say "No," rather than admit the truth. This is an example of

A) confounding.
B) anecdotal evidence.
C) sampling error.
D) nonsampling error.

Question 19

To obtain faculty opinions on a particular issue, the chief academic officer started with the five schools making up the university. Within each school, she randomly selected two departments. Once the departments were selected, seven faculty members in those departments were selected at random (or all if there were fewer than seven) to be interviewed. This is an example of:

A) simple random sampling.
B) cluster sampling.
C) stratified random sampling.
D) sampling in stages.

Question 20

When a sample survey asks people about their age or some physical characteristic, such as weight, some people who feel self-conscious may not give accurate responses.

A) This is a sampling error that causes bias.
B) This is a sampling error that increases variability.
C) This is a nonsampling error that causes bias.
D) This is a nonsampling error that increases variability.

Question 21

A Gallup Poll contacts people by dialing telephone numbers at random. A possible source of nonsampling error in this poll is that

A) some people chosen for the sample refused to answer questions.
B) people without telephones could not be in the sample.
C) some people never answered the phone in several calls.
D) Both A and C are correct.
E) Answers A, B, and C are correct.

Question 22

Which of the following is NOT a potential problem with Internet surveys?

A) Voluntary response
B) Multimedia content
C) Undercoverage
D) Nonresponse

Question 23

A poll conducted telephone interviews with 1497 adults. These 1497 people make up the

A) population.
B) sampling frame.
C) sample.
D) response variable.

Question 24

A recently conducted poll omitted people without telephones, and it also left out Alaska and Hawaii residents to reduce cost. These omissions may cause a small bias. If so, that bias is

A) a sampling error.
B) a nonsampling error.
C) due to voluntary response.
D) due to absence of a control group.

Question 25

The announced margin of error for a sample survey covers

A) nonresponse error.
B) random sampling error.
C) undercoverage error.
D) All of the above

Question 26

Bias can result from

A) how the sample was chosen.
B) how the survey question was worded.
C) Both A and B are correct.
D) None of the above

Question 27

A simple random sample is

A) any sample selected by using chance.
B) any sample that gives every individual the same chance to be selected.
C) a sample that gives every possible sample of the same size the same chance to be selected.
D) a sample that selects equal numbers of individuals from each stratum.
E) a sample that contains the same percent of each subgroup in the population.

Question 28

A sample that is chosen in stages is a sample in which

A) every member of the population has the same chance of being selected.
B) the population is first divided into groups of similar individuals, then a separate simple random sample is selected from each group and combined to form the full sample.
C) every possible sample of the same size has the same chance of being selected.
D) we choose the final sample in several steps; for example, first states, then counties in those states, then households in those counties.

Question 29

Among the following, which is not a question one needs to ask before believing a poll?

A) Who carried out the survey?
B) How was the sample selected?
C) Was the study ever conducted before?
D) What were the exact questions asked?

Question 30

When we take a census, we

A) run the risk of creating an undercoverage situation.
B) collect data from every individual in the sampling frame.
C) collect data from every individual in the population.
D) will likely end up with biased results.

Question 31

A probability sample is a

A) type of voluntary response sample.
B) type of census.
C) type of convenience sample.
D) sample that is chosen by chance.

Question 32

One source of error in pre-election polls is that some people in the sample say they are undecided, but in fact, they know whom they are going to vote for. This is an example of:

A) a nonsampling error.
B) a random sampling error.
C) a sampling error, but not a random sampling error.
D) incorrect randomization.

Question 33

A poll about the effects of marijuana legalization questioned 1025 Denver residents and 472 Colorado citizens from outside Denver. The design of the sample chose separate samples from the two groups and planned to interview more Denver residents than other Coloradans. This is a:

A) systematic random sample.
B) census.
C) stratified random sample.
D) simple random sample.

Question 34

A simple random sample of people is collected and their blood pressures are measured by one of several lab assistants. One of the lab assistants incorrectly reads the blood pressure gauge and records erroneous data. Which of the following types of errors is present here?

A) Margin
B) Nonsampling
C) Sampling
D) Nonresponse

Question 35

One source of error in pre-election polls is that some people in the sample do not tell the truth about who they will vote for. This is an example of

A) a nonsampling error.
B) a random sampling error.
C) a sampling error, but not a random sampling error.
D) incorrect randomization.

Question 36

Some common sources of nonsampling error in samples of human populations are

A) voluntary response samples; can't contact some subjects.
B) can't contact some subjects; some subjects refuse to answer.
C) some subjects refuse to answer; using telephone directory as the sample frame.
D) Answers A, B, and C are correct.
E) None of the above