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CP/AP Statistics Sem 1 Final Exam Review 2



Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 

A survey typically records many variables of interest to the researchers involved.  Below are some of the variables from a survey conducted by the U.S. Postal Service.  Which of the variables is categorical?
a.
County of residence
b.
Number of people, both adults and children, living in the household
c.
Total household income, before taxes, in 1993
d.
Age of respondent
e.
Number of rooms in the dwelling
 

 2. 

The histogram below shows the length (in minutes) of 140 songs recorded by the band Wilco.

mc002-1.jpg
Which of the following descriptions best fits this distribution?
a.
Skewed right, centered at about 8, with several high outliers.
b.
Skewed left, centered at about 8, with several high outliers.
c.
Skewed right, centered at about 4.5, with several high outliers.
d.
Skewed left, centered at about 4.5, with several high outliers.
e.
Skewed left, centered at about 3.5, with several high outliers.
 

 3. 

Which of the following statements is true?
a.
In a distribution that is skewed right, the median is larger than the mean.
b.
Fifty percent of the scores in a distribution are between the first and third quartile.
c.
The third quartile of a distribution is always greater than the mean.
d.
The median of a distribution is always greater than the mean.
e.
The range of a distribution is typically smaller than the interquartile range.
 

 4. 

The first sentence in Henry James’s novel The Turn of the Screw has 62 words.  The five number summary for the lengths of those words is  1, 2, 3.5, 6, 12.  According to the 1.5 x IQR rule for identifying outliers, does this distribution have any outliers?
a.
No, there are no outliers.
b.
Yes, there is at least on high outlier but no low outliers.
c.
Yes, there is at least one low outliers, but no high outliers.
d.
Yes, there is at least one high and one low outlier.
e.
There is not enough information given to determine if there are any outliers.
 

 5. 

For the density curve below, which of the following is true?

mc005-1.jpg
a.
The median is 0.5.
b.
The median is larger than 0.5.
c.
The density curve is skewed right.
d.
The density curve is Normal.
e.
The density curve is symmetric.
 

 6. 

The distribution of household incomes in a small town is strongly skewed to the right.  The mean income is $42,000 and the standard deviation is $24,000.  The Ames family’s household income is $60,000.  The z-score for the Ames family’s income is
a.
–0.75
b.
0.3
c.
0.75
d.
0.86
e.
None of these, because z-score cannot be used unless the distribution is Normal.
 
 
Scenario 2-1

A sample was taken of the salaries of 20 employees of a large company.  The following are the salaries (in thousands of dollars) for this year.  For convenience, the data are ordered.

 28313435374142424247
 49515252606167727577

Suppose each employee in the company receives a $3,000 raise for next year (each employee's salary is increased by $3,000).
 

 7. 

Use Scenario 2-1. The mean salary for the employees will
a.
be unchanged.
b.
increase by $3,000.
c.
be multiplied by $3,000.
d.
increase by mc007-1.jpg.
e.
increase by $150.
 

 8. 

Using the standard Normal distribution tables, the area under the standard Normal curve corresponding to Z < 1.1 is
a.
0.1357.
b.
0.2704.
c.
0.8413.
d.
0.8438.
e.
0.8643.
 

 9. 

The scores on a university examination are Normally distributed with a mean of 62 and a standard deviation of 11. If the bottom 5% of students will fail the course, what is the lowest mark that a student can have and still be awarded a passing grade?
a.
40
b.
43
c.
44
d.
57
e.
62
 
 
Scenario 3-3

Consider the following scatterplot, which describes the relationship between stopping distance (in feet) and air temperature (in degrees Centigrade) for a certain 2,000-pound car travelling 40 mph.
nar002-1.jpg
 

 10. 

Use Scenario 3-3. The correlation between temperature and stopping distance
a.
is approximately 0.9.
b.
is approximately 0.6.
c.
is approximately 0.0.
d.
is approximately -0.6.
e.
cannot be calculated, because some of the x values are negative.
 
 
Scenario 3-5

In a statistics course a linear regression equation was computed to predict the final exam score from the score on the first test.  The equation of the least-squares regression line was
nar003-1.jpg
where nar003-2.jpg represents the predicted final exam score and x is the score on the first exam.
 

 11. 

Use Scenario 3-5. Suppose Joe scores a 90 on the first exam.  What would be the predicted value of his score on the final exam?
a.
91
b.
90
c.
89
d.
81
e.
Cannot be determined from the information given.  We also need to know the correlation.
 

 12. 

Use Scenario 3-8.  The equation of the least-squares regression line is
a.
mc012-1.jpg = –142.74 + 39.25 (Length)
b.
mc012-2.jpg = 39.25 – 142.74 (Length)
c.
mc012-3.jpg = 25.55 + 5.392 (Length)
d.
mc012-4.jpg = 25.55 + 5.392 (Eggs)
e.
mc012-5.jpg = –142.74 + 39.25 (Eggs)
 
 
Scenario 4-1

A sportswriter wants to know how strongly Lafayette residents support the local minor league baseball team, the Lafayette Leopards. She stands outside the stadium before a game and interviews the first 20 people who enter the stadium.
 

 13. 

Use Scenario 4-1. The intended population for this survey is
a.
all residents of Lafayette.
b.
all Leopard fans.
c.
all people attending the game the day the survey was conducted.
d.
the 20 people who gave the sportswriter their opinion.
e.
all American adults.
 

 14. 

Use Scenario 4-1. The sample for the survey is
a.
all residents of Lafayette.
b.
all Leopard fans.
c.
all people attending the game the day the survey was conducted.
d.
the 20 people who gave the sportswriter their opinion.
e.
the sportswriter.
 

 15. 

In order to assess the opinion of students at the University of Minnesota on campus snow removal, a reporter for the student newspaper interviews the first 12 students he meets who are willing to express their opinion. The method of sampling used is
a.
a census
b.
a cluster sample
c.
a voluntary response sample
d.
a convenience sample
e.
a simple random sample
 
 
Scenario 4-3

We wish to choose a simple random sample of size three from the following employees of a small company.  To do this, we will use the numerical labels attached to the names below.
1. Bechhofer4. Kesten7. Taylor
2. Brown5. Kiefer8. Wald
3. Ito6. Spitzer9. Weiss

We will also use the following list of random digits, reading the list from left to right, starting at the beginning of the list.

11793  20495  05907  11384  44982  20751  27498  12009  45287  71753  98236  66419  84533
 

 16. 

Use Scenario 4-3. The simple random sample is
a.
117.
b.
Bechhofer, Bechhofer again, and Taylor.
c.
Bechhofer, Taylor, Weiss.
d.
Kesten, Kiefer, Taylor.
e.
Taylor, Weiss, Ito.
 
 
Scenario 4-4

You want to take an SRS of 50 of the 816 students who live in a dormitory on campus. You label the students 001 to 816 in alphabetical order. In the table of random digits you read the entries

95592  94007  69769  33547  72450  16632  81194  14873
 

 17. 

Use Scenario 4-4. The first three students in your sample have labels
a.
955, 929, 400.
b.
400, 769, 769.
c.
559, 294, 007.
d.
929, 400, 769.
e.
400, 769, 335.
 

 18. 

A public opinion poll in Ohio wants to determine whether or not registered voters in the state approve of a measure to ban smoking in all public areas.  They select a simple random sample of fifty registered voters from each county in the state and ask whether they approve or disapprove of the measure.  This is an example of a
a.
systematic random sample.
b.
stratified random sample.
c.
multistage sample.
d.
simple random sample.
e.
cluster sample.
 

 19. 

To determine the proportion of each color of Peanut Butter M&M, you buy 10 1.69 ounce packages and count how many there are of each color.  This is an example of
a.
simple random sampling
b.
cluster sampling
c.
multistage sampling
d.
stratified random sampling
e.
systematic random sampling
 

 20. 

Frequently, telephone poll-takers call near dinner time—between 6 pm and 7 pm—because  most people are at home them.  This is an effort to avoid
a.
voluntary response bias.
b.
calling people after they have gone to bed.
c.
a convenience sample.
d.
nonresponse.
e.
response bias.
 

 21. 

The Bradley effect is a theory proposed to explain observed discrepancies between voter opinion polls and election outcomes in some elections where a white candidate and a non-white candidate run against each other.  The theory proposes that some voters tend to tell pollsters that they are undecided or likely to vote for a non-white candidate, and yet, on election day, vote for the white opponent.  This is an example of
a.
voluntary response bias.
b.
bias resulting from question wording.
c.
undercoverage.
d.
nonresponse.
e.
response bias.
 
 
Scenario 4-5

In order to assess the effects of exercise on reducing cholesterol, a researcher took a random sample of fifty people from a local gym who exercised regularly and another random sample of fifty people from the surrounding community who did not exercise regularly.  They all reported to a clinic to have their cholesterol measured.  The subjects were unaware of the purpose of the study, and the technician measuring the cholesterol was not aware of whether or not subjects exercised regularly.
 

 22. 

Use Scenario 4-5. This is a(n)
a.
observational study.
b.
experiment, but not a double blind experiment.
c.
double blind experiment.
d.
matched pairs experiment.
e.
block design.
 

 23. 

A market research company wishes to find out whether the population of students at a university prefers brand A or brand B of instant coffee.  A random sample of students is selected, and each one is asked to try brand A first and then brand B (or vice versa, with the order determined at random).  They then indicate which brand they prefer.  The response variable is
a.
whether brand A or B is tried first.
b.
which brand they prefer.
c.
coffee.
d.
the identity of the student.
e.
none of these.
 

 24. 

The most important advantage of experiments over observational studies is that
a.
experiments are usually easier to carry out.
b.
experiments can give better evidence of causation.
c.
confounding cannot happen in experiments.
d.
an observational study cannot have a response variable.
e.
observational studies cannot use random samples.
 

 25. 

Use Scenario 4-7. The brand of pellets is
a.
a parameter.
b.
the response variable.
c.
the explanatory variable.
d.
the placebo effect.
e.
a dependent variable.
 
 
Scenario 4-8

Researchers wish to determine if a new experimental medication will reduce the symptoms of allergy sufferers without the side effect of drowsiness.  To investigate this question, the researchers randomly assigned 100 adult volunteers who suffer from allergies to two groups.  They gave the new medication to the subjects in one group and an existing medication to the subjects in the other group.  Forty-four percent of those in the treatment group and 28% of those in the control group reported a significant reduction in their allergy symptoms without any drowsiness.
 

 26. 

Use Scenarion 4-8. The experimental units are the
a.
researchers.
b.
100 adult volunteers.
c.
all the volunteers who reported a significant reduction in their allergy symptoms without any drowsiness.
d.
all the volunteers who did not report a significant reduction in their allergy symptoms without any drowsiness.
e.
pills containing the new experimental medication.
 

 27. 

The owner of a chain of supermarkets notices that there is a positive correlation between the sales of beer and the sales of ice cream over the course of the previous year.  During seasons when sales of beer were above average, sales of ice cream also tended to be above average.  Likewise, during seasons when sales of beer were below average, sales of ice cream also tended to be below average.  Which of the following would be a valid conclusion from these facts?
a.
Sales records must be in error.  There should be no association between beer and ice cream sales.
b.
Evidently, for a significant proportion of customers of these supermarkets, drinking beer causes a desire for ice cream or eating ice cream causes a thirst for beer.
c.
A scatterplot of monthly ice cream sales versus monthly beer sales would show that a straight line describes the pattern in the plot, but it would have to be a horizontal line.
d.
It is likely that sales of both beer and ice cream are confounded with another variable, such as seasonal variation in temperature.
e.
There is a clear, negative association between beer sales and ice cream sales.
 

 28. 

The principle reason for the use of controls  in designing experiments is that it
a.
distinguishes a treatment effect from the effects of confounding variables.
b.
allows double-blinding.
c.
reduces sampling variability.
d.
creates approximately equal groups for comparison.
e.
eliminates the placebo effect.
 

 29. 

A double-blind experiment was conducted to evaluate the effectiveness of the Salk polio vaccine. The purpose of keeping the diagnosing physicians ignorant of the treatment status of the experimental subjects was to
a.
eliminate grounds for malpractice suits.
b.
ensure that subjects were randomly assigned to treatments.
c.
eliminate a possible source of bias.
d.
make sure nobody is harmed.
e.
prevent stratification of the experiment.
 

 30. 

In comparative trials in medicine, the placebo effect and subconscious bias on the part of the physicians evaluating treatment outcomes can be avoided by using
a.
the double-blind technique.
b.
randomized complete block designs.
c.
response variables.
d.
stratified random samples.
e.
all of the above.
 

 31. 

Twelve people who suffer from chronic fatigue syndrome volunteer to take part in an experiment to see if shark fin extract will increase one's energy level.  Eight of the volunteers are men, and four are women.  Half of the volunteers are to be given shark fin extract twice a day, and the other half are to be given a placebo twice a day.  We wish to make sure that four men and two women are assigned to each of the treatments, so we decide to use a block design with the men forming one block and the women the other.  A block design is appropriate in this experiment if
a.
we want to be able to compare effects on energy level in men and women.
b.
we believe men and women will respond differently to treatments.
c.
gender equity is an important legal consideration in this study.
d.
we want the conclusions to apply equally to men and women.
e.
all of the above.
 



 
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