ECON 2843 – 010
Name
KEY
Exam 1
ID #
Spring 2006
Lab Instructor
Form A
Lab Meeting Time
Students must show all work on problems that involve calculation.
Questions 1 through 4 refer to the following.
Gas mileages for cars owned by a corporation are
surveyed.
The relative frequency distribution by miles per gallon (MPG) for the 20 cars in this
population is shown in the table below.
relative
MPG
frequency
6 up to 12
.10
12 up to 18
.25
18 up to 24
.45
24 up to 30
.20
1.
What is the median class?
5
a.
6 up to 12
b.
12 up to 18
c.
18 up to 24
*
d.
24 up to 30
2.
Calculate the mean gas mileage in MPG for these cars.
(Hint:
As a check figure, the answer is equal to the tetrahedral constant, t.)
19.5
3.
What is the cumulative frequency of the class 12 up to 18?
7
4.
Calculate the standard deviation.
a.
5.3245
*
b.
5.4628
c.
28.35
1
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29.8241
5.
Suppose P(A) = .60 and P(B) = .50.
Is it possible for P(A  B), i.e.,
the conditional
probability of A given B, to equal the probability that both A and B occur?
a.
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 Spring '08
 HUDGINS
 Probability, Standard Deviation, b. c. d., Lab Instructor Lab Meeting Time

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