ECON 2843
Name
KEY
Exam 1
ID #
Fall 2007
Lab instructor
Form A
Meeting Time
Students must show all work on problems that involve calculation.
Questions 1 through 4 refer to the following.
The manager of the helpline at a local software
manufacturing firm collected data on the number of calls the help desk received per shift for the
last 100 days. The data is summarized in the table below.
Number of Calls
Number of Days
80 – under 120
1
120 – under 160
21
160– under 200
29
200 – under 240
32
240 – under 280
15
280 – under 320
2
1.
What is the standard deviation of this sample?
(8 points)
5
a.
42.8486
b.
43.0644
*
c.
1836
d.
1854.55
e.
3080
2.
Calculate the coefficient of variation.
(6 points)
21.75%
3.
What is the probability that the number of calls on a randomly selected day will be less
than or equal to the number of calls in the median class?
(6 points)
.51
4.
What is the cumulative frequency of the class 240 – under 280?
(6 points)
98
1
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View Full DocumentQuestions 5 – 8 refer to the following.
“Just when you thought the mommy wars were over, a new study shows the divide has grown
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 Spring '08
 HUDGINS
 Normal Distribution, Standard Deviation, ideal situation

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