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Practice 2 for midterm exam: ChE220
Please Note: You are not responsible for questions 20, 26, 27, 28, and 29 for this midterm.
1.
A customs agent rolls an ordinary die as each traveler arrives at the customs station. If
the die comes up 6 the traveller’s luggage is searched thoroughly. Otherwise, the
traveler is allowed to pass without a thorough search. Which one of the following is
correct?
A) One out of every 6 travelers receives a thorough search.
B) After many travelers have gone through customs, about 60% of them will have
been subjected to a thorough search.
C) After many travelers have gone through customs, about 12.5% of them will have
been subjected to a thorough search.
D) Five out of every six travelers is allowed to pass without a thorough search.
E) None of the above.
2.
There are 150 women in a group of college graduates. Another group consists of 800
women who ended their education after graduating from high school. Which of the
following tools would be best suited for comparing starting salaries for the two
groups?
A) Cumulative distribution plot.
B) Dotplots
C) Stemandleaf diagrams
D) Frequency Histograms
E) Box plots
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View Full Document 3.
A dataset of 23 values of a variable has a mean of 10.8 and a standard deviation of 3.2
The third data value is 9.2. What is the value of the
deviation from the mean
for this
third data value?
A) (9.2 – 10.8)/3.2
B)
(9.2 – 10.8)
2
C)
(9.2 – 10.8)
2
/22
D)
(9.2 – 10.8)
2
/23
E) (9.2 – 10.8)
4.
Incomes were reported in whole thousands of dollars. The histogram of the incomes
is shown below. Based on the histogram, what percent of incomes are
above
17
thousand dollars?
Histogram of Income N
=
10
Midpoint
Count
10.00
1
*
15.00
5
*****
20.00
3
***
25.00
1
*
A) 10
B) 20
C) 30
D) 40
F) None of the above
5.
Outliers (extreme observations large of small) affect the following:
I.
The median
II.
The interquartile range
III.
The quartiles
A) I and II only
B) II and III only
C) I and III only
D) I, II, and III
E) None of the above.
6.
For any set of data, the sum of the deviations from the mean is zero.
A) True
B)
False
7.
A histogram based on many narrow class intervals will fail to show the overall pattern
in a distribution.
A) True
B)
False
8.
A skewed distribution has left and right sides that are mirror images of one another.
A) True
B)
False
9.
For the data 4, 2, 10, 8, what is the value of the sum of squared deviations from the
mean?
A) 0
B) 6
C) 40
D) 184
E) None of the above
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View Full Document 10. The mean annual income of 20 women is $22,000 and the mean annual income of 10
men is $19,000. What is the mean annual income of the combined group of 30
people?
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This note was uploaded on 10/08/2010 for the course CHE 220 taught by Professor Elkamel during the Spring '10 term at Waterloo.
 Spring '10
 Elkamel

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