STA 2023 Test #1 Practice Multiple Choice
1.
An office supply catalog gives a description of bookshelves which includes the
following variables. Which of these variables is categorical?
A)
The width of a bookshelf in inches.
B)
The width of a bookshelf in feet.
C)
The color of the bookshelf.
D)
The height of a bookshelf in inches.
2.
A particularly common question in the study of wildlife behavior involves
observing contests between 'residents' of a particular area and 'intruders.' In each
contest, the 'residents' either win or lose the encounter (assuming there are no
ties). Observers might record several variables, listed below. Which of these
variables is categorical?
A)
The duration of the contest (in seconds).
B)
The number of animals involved in the contest.
C)
Whether the 'residents' win or lose.
D)
The total number of contests won by the 'residents.'
3.
A professor records the values of several variables for each student in her class.
These include the variables listed below. Which of these variables is categorical?
A)
Score on the final exam (out of 200 points).
B)
Final grade for the course (A, B, C, D, or F).
C)
The total number of points earned in the class (i.e., the total of the points
on all exams and quizzes in the course. The maximum number of points
possible is 500).
D)
The number of lectures the student missed.
4.
A consumer group surveyed the prices for a certain item in five different stores,
and reported the average price as $15. We visited four of the five stores, and
found the prices to be $10, $15, $15, and $25. Assuming that the consumer group
is correct, what is the price of the item at the store that we did not visit?
A)
$10.
B)
$15.
C)
$20.
D)
$25.
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5.
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.
28
49
31
51
34
52
35
52
37
60
41
61
42
67
42
72
42
75
47
77
Suppose each employee in the company receives a $3,000 raise for next year
(each employee's salary is increased by $3,000). The mean salary for the
employees will
A)
be unchanged.
B)
increase by $3,000.
C)
be multiplied by $3,000.
D)
increase by 3000 .
6.
The standard deviation of the salaries for the employees in exercise #5 will
A)
be unchanged.
B)
increase by $3,000.
C)
be multiplied by $3,000.
D)
increase by 3000 .
7.
The median of the data from exercise #5 is
A)
$42,000.
B)
$47,000.
C)
$48,000.
D)
$49,000.
8.
The first quartile of the data from exercise #5 is
A)
$35,000.
B)
$36,000.
C)
$37,000.
D)
$39,000.
9.
Referring to the data from exercise #5, the interquartile range (IQR) of this data is
A)
$19,000.
B)
$19,500.
C)
$21,500.
D)
$49,000.
10.
Referring to the data from exercise #5, suppose each employee in the company
receives a $3,000 raise for next year (each employee’s salary is increased by
$3,000). The interquartile range of the salaries for the employees will
A)
be unchanged.
B)
increase by $3,000.
C)
be multiplied by $3,000.
D)
increase by 3000 .
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11.
This is a standard deviation contest. Which of the following sets of four numbers
has the largest possible standard deviation?
A)
7, 8, 9, 10.
B)
5, 5, 5, 5.
C)
0, 0, 10, 10.
D)
0, 1, 2, 3.
Consider the stemplot below. Use this to answer questions #12 and #13.
1|
2|
3|
4|
5|
6|
6
2
0
0
0
1
4
1
5
1
8 9
1 2 3 4 5 6 7 8
8
8
12.
Consider the above stem plot. The third quartile Q3 of the data represented in this
stem plot is approximately
A)
24.
B)
35.
C)
45.
D)
50.
13.
The IQR for the data represented by the stemplot above is:
A)
15.
B)
30.
C)
45.
D)
60.
14.
The standard deviation of 10 measurements of people's height (in inches) is
computed to be 25. The variance of these measurements is
A)
5.
B)
100.
25
.
C)
10
D)
625.
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15.
A researcher reports that, on average, the participants in his study lost 10.4 lbs.
after two months on his new diet. A friend of yours comments that she tried the
diet for two months and lost no weight, so clearly the report must be a fraud.
Which of the following statements is correct?
A)
Your friend must not have followed the diet correctly, since she did not
lose weight.
B)
Since your friend did not lose weight, the report must not be correct.
C)
The report only gives the average. This does not imply that all
participants in the study lost 10.4 lbs. or even that all lost weight. Your
friend's experience does not necessarily contradict the study results.
D)
In order for the study to be correct, we must now add your friend's results
to those of the study and recompute the new average.
16.
The mean age of five people in a room is 30 years. One of the people whose age
is 50 years leaves the room. The mean age of the remaining four people in the
room is
A)
40.
B)
30.
C)
25.
D)
cannot be determined from the information given.
17.
The ages of people in a class (to the nearest year) are as follows:
Age 18
Number of Students 14
19
120
20
200
21
200
22
90
23
30
24
10
25
2
32
1
What is true abut the median age?
A)
It must be 20.
B)
It could be any number between 19 and 21.
C)
It must be 21.
D)
It must be over 21.
18.
The five-number summary of a set of data is
A)
the minimum, first quartile, median, third quartile, and maximum.
B)
the mean, median, mode, variance, and standard deviation.
C)
any five-digit number that describes the data.
D)
any five single-digit numbers that are measures of center and spread.
19.
The median age of five people in a meeting is 30 years. One of the people, whose
age is 50 years, leaves the room. The median age of the remaining four people in
the room is
A)
40 years.
B)
30 years.
C)
25 years.
D)
cannot be determined from the information given.
4
Consider the following box plot of the exam scores in a statistics course
to answer questions #20 and #21.
90
exam scores
80
70
60
50
40
30
20.
The median score was approximately
A)
90.
B)
65.
C)
75.
D)
60.
21.
The interquartile range is approximately
A)
16.
B)
55.
C)
65.
D)
5.
22.
A reporter wishes to portray baseball players as overpaid. Which measure of
center should he report as the average salary of major league players?
A)
The mean.
B)
The median.
C)
Either the mean or median. They will be equal in this case.
D)
Neither the mean nor the median. Both will be much lower than the actual
average salary.
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23.
In a class of 100 students, the grades on a statistics test are summarized in the
following frequency table.
Grade Frequency
91-100 11
81-90 31
71-80 42
61-70 16
The median grade is in which of the following intervals?
A)
61-70
B)
71-80
C)
81-90
D)
91-100
24.
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. This study is
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.
25.
An experiment is said to be biased if
A)
it allows racial or gender differences in the subjects taking part in the
experiment.
B)
it is conducted in such a way as to systematically favor certain outcomes.
C)
the researcher has speculated in advance as to what the outcome might be.
D)
it allows individuals with strong opinions to take part in the experiment.
26.
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 a placebo twice a day. Suppose one of the
researchers is responsible for determining if a subject displays an increase in energy
level. In this case, we should probably
A)
use two placebos.
B)
use stratified sampling to assign subjects to treatments.
C)
use fewer subjects but observe them more frequently.
D)
conduct the study as a double-blind experiment.
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27.
Which of the following is not a major principle of experimental design?
A)
comparative experimentation.
B)
replication.
C)
randomization.
D)
segmentation.
28.
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 of movie
was shown at 8 A.M. (right after the children had breakfast) and another at 11 A.M. (right
before the children had lunch). 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. The results cannot
be trusted because
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.
29.
An amateur gardener decides to change varieties of tomatoes for this year to see if
the yield is improved. He put in six plants the previous year and six plants this year using
the same part of the garden. The average yield per plant was 11.3 pounds per plant in the
previous year and 14.5 pounds per plant using the new variety. This is an example of
A)
an experiment.
B)
an observational study, not an experiment.
C)
the elimination of all confounding variables by design, since the gardener
used the same part of the garden in both years.
D)
a multistage design, since two years were involved.
30.
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 give the new medication to 50 adult volunteers who suffer from
allergies. 44 of these volunteers report a significant reduction in their allergy symptoms
without any drowsiness. This study could be improved by
A)
including people who do not suffer from allergies in the study in order to
represent a more diverse population.
B)
repeating the study with only the 44 volunteers who reported a significant
reduction in their allergy symptoms without any drowsiness, and giving
them a higher dosage this time.
C)
using a control group.
D)
all of the above.
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31.
In order to assess the opinion of students at the Ohio State University, a reporter
for the student newspaper interviews the first six students he meets who are willing to
express their opinion. In this case, the population is
A)
all reporters for the newspaper.
B)
all student newspapers of American colleges and universities.
C)
the 6 students interviewed.
D)
all students at the Ohio State University.
32.
A public opinion poll in Ohio wants to determine whether registered voters in the
state approve of a measure to ban smoking in all public areas. They select a simple
random sample of 50 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 county sample.
B)
a stratified sample.
C)
a multistage sample.
D)
a simple random sample.
33.
The Chronicle of Higher Education (Jan. 29, 1999) published data collected in a
survey of a very large number of students who were college freshmen in the fall of 1998.
One question asked whether the student was attending his or her first, second, or third
choice of university. Fourth or higher choices were combined in a category called
“other.” The resulting data is summarized in the pie chart below.
First
Other
Second
Third
Based on this pie chart, we may conclude that
A)
Over 50% of the universities are first choice.
B)
Freshmen who answered “third” are least likely to attend their university.
This is because their slice of the pie is at the bottom of the chart.
C)
Less than 25% of the freshmen attended their second choice university.
D)
The pie chart is incorrect since fourth choice should have been included.
34.
Suppose that you and your friends emptied pockets of coins and recorded the year
since 1900 from the date marked on each coin. The distribution of your data would be
A)
skewed left.
B)
skewed right.
C)
symmetric.
D)
uniform.
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ANSWER KEY:
1. C
2. C
3. B
4. A
5. B
6. A
7. C
8. D
9. C
10. A
11. C
12. C
13. A
14. D
15. C
16. C
17. A
18. A
19. D
20. B
21. A
22. A
23. B
24. C
25. B
26. D
27. D
28. D
29. B
30. C
31. D
32. B
33. C
34. A
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