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Economic Statistics Exam 3
Name:
Summer 2009
PID:
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This exam contains
twenty
short answer questions
(
worth 6 points each
)
and
four
long answer questions
(
worth 15 points each
)
. Show your work clearly to be eligible
for partial credit. In all problems where you need to make a calculation, simplify your
answer as much as convenient. In questions with multiple parts, you should respond
as if your answers to previous parts were correct.
Short Questions
(
6 points apiece
)
1. When testing a hypothesis, there are two mistakes we can make. Name and
describe these errors.
2. Mulberry trees are either male or female; each sex is equally likely. In order to get
fruit, I will need one of each sex. Unfortunately, I can purchase only “unsexed”
saplings, where the sex hasn’t been identified. How many saplings must I purchase in
order to have at least a
0.75
chance of having at least one of each sex?
3. What is wrong with creating a pie chart, and then labeling the percentage of the
sample that belongs in each wedge?
4. A random variable
X
takes on the values
1,2,3,4,5
with equal probability. What is
the variance in
X
?
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View Full DocumentEcon 400 Exam 3, page 2 of 9.
5. According to my best calculations, there is a
0.20
chance that modern civilization
collapses in the next year, a
0.30
chance that the current swine flu goes pandemic,
and a
0.15
chance of both. What is the chance that
neither
disaster occurs?
6. Given that the swine flu pandemic happens, what is the chance that civilization
collapses?
7. Construct a box

and

whisker plot with these numbers:
1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1597
8. What is the rule of thumb for approximating the standard deviation using the
range of a sample?
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 Fall '08
 turchi

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