Chapter 3 Quiz

Name:

1.  What is a sample of size n chosen in such a way that every set of n units in the population has an equal chance to be the sample actually selected?

A.   simple random sample
B.   block design
C.   comparative study
D.   stratified random sample
E.   None of These

2.  What is bias?

A.   systematic error in the way a sample represents a population
B.   racial prejudice on the part of the experimenters
C.   falsified data, resulting from pre-conceived ideas about the results
D.   a situation in which two errors cancel one another
E.   None of These

3.  A study to determine whether or not a kicking a football filled with helium traveled farther than one filled with air found that, while the football filled with helium went, on average, farther than the one filled with air, the difference was not statistically significant. What does the phrase "not statistically significant" mean?

A.   the observed difference could plausibly have arisen by chance.
B.   the difference was not enough to have an important impact on kicking statistics.
C.   some, but not all kickers will benefit from kicking a helium filled football.
D.   the study was poorly designed and a statistician should have been consulted.
E.   None of These

4.  A study to determine whether or not a kicking a football filled with helium traveled farther than one filled with air found that, while the football filled with helium went, on average, farther than the one filled with air, the difference was not statistically significant. What are the treatments?

A.   the gas, air or helium, with which the football is filled
B.   whether or not the football was kicked
C.   the kickers
D.   the distance, on average, which the football traveled
E.   None of These
Can pleasant aromas help a student learn better? Two researchers believed that the presence of a floral scent could improve a person's learning ability in certain situations. They had twenty-two people work through a pencil and paper maze six times, three times while wearing a floral-scented mask and three times wearing an unscented mask. The three trials for each mask closely followed one another. Testers measured the length of time it took subjects to complete each of the six trials. They reported that, on average, subjects wearing the floral-scented mask completed the maze more quickly than those wearing the unscented mask, although the difference was not statistically significant.

5.  What is the above study?

A.   a convenience sample
B.   an observational study, not an experiment
C.   an experiment, but not a double blind experiment
D.   a double blind experiment
E.   None of These

6.  In the above study, what is the factor (explanatory variable)?

A.   the maze
B.   the presence or absence of the floral scent
C.   wearing a mask
D.   the length of time to complete the maze
E.   None of These

7.  In the above study, what does the phrase "not statistically significant" mean?

A.   the difference was not enough to have an important impact on teaching practice
B.   the subjects were unable to distinguish between the scented and unscented mask except in a few "random" instances
C.   the study was poorly designed and a statistician should have been consulted
D.   the observed difference could plausibly have arisen by chance
E.   None of These

8.  An experiment was conducted by some students to explore the nature of the relationship between a person's heart rate (measured in beats per minute) and the frequency at which that person stepped up and down on steps of various heights. There were three rates of stepping and two different step heights used. A subject performed the activity (stepping at a one of the three stepping rates at one of the two possible heights) for three minutes. Heart rate was then measured at the end of this period.

What are the variables "stepping rate" and "step height"?

A.   the factors
B.   the levels
C.   the controls
D.   the units
E.   None of These

9.  A study of human development showed two types of movies to groups of children. Crackers were available in a bowl, and the investigators compared the number of crackers eaten by children watching the different kinds of movies. One kind was shown at 8 A.M. and another at 11 A.M. It was found that during the movie shown at 11 A.M., more crackers were eaten than during the movie shown at 8 A.M. The investigators concluded that the different types of movies had an effect on appetite. Why cannot the results of the above experiment be trusted?

A.   The study was not double blind. Neither the investigators nor the children should have been aware of which movie was being shown.
B.   The investigators were biased. They knew beforehand what they hoped the study would show.
C.   The investigators should have used several bowls, with crackers randomly placed in each.
D.   The time the movie was shown is a lurking variable.
E.   None of These

10.  What are the treatments in the above experiment?

A.   the crackers
B.   the types of movies
C.   the children
D.   the use of bowls
E.   None of These

11.  A study sponsored by Chrysler contends that more Americans preferred a Chrysler to a Toyota after test driving both. The study was conducted using 100 people in each of two separate tests involving both auto makers. None of the subjects owned a foreign car. The results of this study are probably ...?

A.   biased understating the popularity of Chrysler
B.   biased overstating the popularity of Chrysler
C.   surprising, but unbiased since this was a comparative experiment
D.   neither surprising nor unbiased, since this was a blinded (subjects had not owned a foreign car) comparative experiment
E.   None of These

12.  What is a specific experimental condition applied to the subjects of an experiment?

A.   an observation
B.   the placebo effect
C.   a treatment
D.   the control
E.   None of These

13.  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 These

14.  What occurs in a double blind experiment?

A.   Both eyes are blindfolded so as to deprive subjects of visual input.
B.   Subjects know neither what they are to do nor when they are to do it.
C.   Neither subjects nor evaluators know what treatment they are receiving.
D.   Units (usually animals) are not allowed to see other units nor the investigators.

15.  Bias in a survey can occur when an individual for the sample can't be contacted or refuses to cooperate. What is this type of bias called?

A.   convenience sampling
B.   response bias
C.   nonresponse
D.   involuntary response

16.  A study sponsored by American Express Co. and the French government tourist office found that old stereotypes about French unfriendliness weren't true. The respondents were more than 1,000 Americans who have visited France more than once for pleasure over the past two years. The results of this study are probably ...

A.   very accurate given the large sample size
B.   very inaccurate since the sample is only a small fraction of all Americans who have visited France
C.   biased, overstating the extent to which the old stereotypes weren't true
D.   biased, understating the extent to which the old stereotypes weren't true
E.   None of These

17.  A call-in poll conducted by USA Today concluded that Americans love Donald Trump. USA Today later reported that 5,640 of the 7,800 calls for the poll came from the offices owned by one man, Cincinnati financier Carl Lindner who is a friend of Donald Trump. The results of this poll are probably what?

A.   surprising, but reliable since it was conducted by a nationally recognized organization
B.   biased, but only slightly since the sample size was quite large
C.   biased understating the popularity of Donald Trump
D.   biased overstating the popularity of Donald Trump
E.   None of These

18.  A 1992 Roper poll found that 22% of Americans say that the Holocaust may not have happened. The actual question asked in the poll was:

"Does it seem possible or impossible to you that the Nazi extermination of the Jews never happened?"

22% responded "possible." Which of the following is a reason why the results of this poll cannot be trusted?

 A.   Undercoverage is present. Obviously those people who did not survive the Holocaust could not be in the poll.
B.   The question is worded in a confusing manner.
C.   We do not know who conducted the poll or who paid for the results.
D.   Nonresponse is present. Many people will refuse to participate and those that do will be biased in their opinions.
E.   None of These

19.  Which of the following is not a potential source of bias in a survey?

A.   undercoverage
B.   nonresponse
C.   the use of convenience sampling
D.   the use of simple random sampling
E.   None of These

20.  The six people listed below are enrolled in a statistics course taught by means of television. Use the list of random digits:

27102 56027 55892 33063 41842 81868 71035 09001 43367 49497 54580 81507

Start at the beginning of this list, to choose a simple random sample of three to be interviewed in detail about the quality of the course. Use the labels attached to the six names:

1. Moore
2. Casella
3. Santner
4. Goel
5. Jones
6. Klein

What is the sample you obtain?

 A.   Moore, Casella, Jones
B.   2, 7, 1
C.   Moore, Casella, and again Casella
D.   any set of 3 names, but we must exclude Casella
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