1
S
TAT
145
–
F
INAL
E
XAM
R
EVIEW
–
S
OLUTIONS
Note:
This review is longer than a final exam would be, but the questions are representative of
the types of questions you could see. There are no guarantees that the final exam “looks like” the
final exam review.
**Multiple Choice** Please circle the best answer.
1.
After conducting a survey at a pet store to see what impact having a pet had on the condition of the
yard, a news reporter stated, “There appears to be a strong correlation between owning a pet and the
condition of the yard.” This statement means
a.
that if a home owner owns a pet, the better the condition of the yard.
b.
that if a home owner owns a pet , the worse the condition of the yard.
c.
that there is a strong relationship between the pet ownership and the condition of the yard, but we
do not know if this relationship is positive or negative.
d.
nothing, since owning a pet and condition of the yard are categorical variables.
2.
Suppose a particular outcome from a random event has a probability of 0.02. Which of the following
statements represent correct interpretations of this probability?
a.
The outcome will never happen.
b.
The outcome will certainly happen two times out of every 100 trials.
c.
The outcome is expected to happen about two times out of every 100 trials.
d.
The outcome could happen, or it couldn't, the chances of either result are the same.
3.
A recent article in an educational research journal reports a correlation of +0.8 between math
achievement and overall math aptitude for a large sample of students. It also reports a correlation of
−
0.8 between math achievement and a math anxiety test for the same group of students. Only students
with scores on all three measures were included in the study. Which of the following interpretations is
the most correct?
a.
The correlation of +0.8 indicates a stronger a relationship than the correlation of 0.8.
b.
The correlation of +0.8 is just as strong as the correlation of
−
0.8.
c.
It is impossible to tell which correlation is stronger.
4.
If a set of data is shifted and rescaled, the standard deviation is
a.
shifted but not rescaled.
b.
shifted and rescaled.
c.
rescaled but not shifted.
d.
neither shifted nor rescaled.
5.
A group of 30 introductory statistics students took a 25item test. The mean and standard deviation
were computed; the standard deviation was 0. You know that
a.
about half of the scores were above the mean
b.
the test was so hard that everyone missed many of the questions
c.
a calculation error must have been made in determining the standard deviation
d.
everyone correctly answered the same number of items
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6.
Suppose we are told that X and Y have a strong correlation, but we do not know whether it is a
positive or negative correlation. The scatterplot tells us, however, that when X is below its mean, Y
tends to be above its mean, and when X is above its mean, Y tends to be below its mean. What is the
sign on the correlation coefficient in this case?
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 Spring '10
 huxangXing
 Economics, Standard Deviation, college students, BlackJack II

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