Economics 120B
Spring 2008
Dr. Maria Cândido
Student Name:_____________________________________
Student ID:________________________________________
Economics 120B Midterm Examination Answer Key
Spring Quarter
May 8
th
, 2008
Version A
Instructions:
a.
You have 80 minutes to finish your exam. Write your name and ID number on the upper left
corner of this page.
b.
Confirm that your test has
10
pages. Make sure you find the formula sheet, as well as the
standard normal distribution table, in the pages of your exam. The last page can be used as
scratch paper.
c.
There are two parts to this exam – multiplechoice questions (Part I) and longer questions
(Part II). You do not need to justify your answers for the multiplechoice questions. Show
ALL your work for the longer questions.
d.
Use a pen to write your answers. You give up your right to a regrade if you choose to use a
pencil.
e.
The table below indicates how points will be allocated on the exam. You can answer the
questions in any order you like. Use your time carefully and efficiently.
Question
Points
Part I
24
Part II
1.
18
2.
16
3.
6
4.
30
5
6
Exam Total
100
f.
With you, you should only have a pen, and a calculator.
g.
You will NOT be allowed to leave the room during the exam. Turn off your cell phone and
your IPod, and good luck!
1
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View Full DocumentEconomics 120B
Spring 2008
Dr. Maria Cândido
PART I: MultipleChoice Questions
(2 points each, 24 points total)
1)
In 20062007, the mean annual cost to attend a private university was $21,180. Assume that the distribution
of annual costs is normal and that the standard deviation is $4,500. 97.5 % of all students at private
universities pay less than what amount?
a.
$28,560
b.
$30,000
c.
$32,790
d.
Not enough information to compute.
2)
A group of college students believes that herbal tea has remarkable restorative powers.
To test its theory,
the group makes weekly visits to a local nursing home, visiting with residents, talking with them and
serving them herbal tea.
After several months, many of the residents are more cheerful and healthy.
Which
of the following may be correctly concluded from this study?
a.
herbal tea does improve one’s emotional state, at least for the residents of nursing homes.
b.
there is some evidence that herbal tea may improve one’s emotional state.
The results would be
completely convincing if a scientist had conducted the study rather than a group of college students.
c.
the results of the study are not convincing since only a local nursing home was used and only for a few
months.
d.
the results of the study are not convincing since the effect of herbal tea is confounded with
several other factors.
3)
In a sample, each 445 college students was classified according to number of cigarettes smoked per month
(Y) and parental use of tobacco (X, where X=0 if neither parent is a smoker, X=1 if only one parent is a
smoker and X=2 if both parents are smokers). The table below shows the joint probability distribution of X
and Y.
Joint Distribution of X and Y
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 Spring '08
 Jeon
 Economics, Statistics, Econometrics, Normal Distribution, Regression Analysis, Statistical hypothesis testing, Dr. Maria Cândido

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