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Econ 3818 Midterm 1
Name:
1. To rate TV shows, phone surveys are sometimes used. Such a survey might record several
variables, some of which are listed below.
Which of these variables is categorical?
a. the number of persons watching the show
b. the ages of all persons watching the show
c. the number of times the show has been watched in the last month
*
d. the name of the show (if any) being watched.
Use the following to answer questions 2 – 3.
In a Business Statistics class with 136 students, the professor records how much money each
student has in his or her possession during the first class of the semester.
The following
histogram is of the data collected.
100
50
0
60
50
40
30
20
10
0
Amount of Money
10 20 30 40
60
2. From the histogram, which of the following is true?
*
a. The mean is much larger than the median.
b. The mean is much smaller than the median.
c. The mean and median are approximately equal.
d. It is impossible to compare the mean and median for these data.
3. From the histogram, the first quartile must be
*
a. in the interval $0 – $10.
b. in the interval $10 – $20.
c. in the interval $30 – $40.
d. $34.
4. There are three children in a room, ages 3, 4, and 5.
If a fouryearold enters the room, the
a. mean age will stay the same, but the variance will increase.
*
b. mean age will stay the same, but the variance will decrease.
c. mean age and variance will stay the same.
d. mean age and variance will increase.
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5. For this density curve, what percent of the observations lie between 0.25 and 0.50?
a. 0.25%
* b. 12.5%
c. 25%
d. 50%
6. A normal density curve has which of the following properties?
a. It is symmetric.
b. It has a peak centered above its mean.
c. The spread of the curve is proportional to the standard deviation.
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 Spring '07
 JessVechibany
 Normal Distribution, Standard Deviation, Major League Baseball, leastsquares regression line

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