Ch4 Testbank Handout PDF
Ch4 Testbank Handout PDF
Ch4 Testbank Handout PDF
True/False
Multiple Choice
46. The test scores for a class of 147 students are computed. What is the location of the test score
associated with the third quartile?
A) 111
B) 37
C) 74
D) 75%
Answer: A
51. Mr. and Mrs. Jones live in a neighborhood where the mean family income is $45,000 with a standard
deviation of $9,000. Mr. and Mrs. Smith live in a neighborhood where the mean is $100,000 and the
standard deviation is $30,000. What is the relative dispersion of the family incomes in the two
neighborhoods?
A) Jones 40%, Smith 20%
B) Jones 20%, Smith 30%
C) Jones 30%, Smith 20%
D) Jones 50%, Smith 33%
E) None of the above
Answer: B
52. A large oil company is studying the number of gallons of gasoline purchased per customer at self-
service pumps. The mean number of gallons is 10.0 with a standard deviation of 3.0 gallons. The median
is 10.75 gallons. What is the Pearson's coefficient of skewness?
A) -1.00
B) -0.75
C) +0.75
D) +1.00
Answer: B
53. What is the value of the Pearson coefficient of skewness for a distribution with a mean of 17, median
of 12 and standard deviation of 6?
A) +2.5
B) -2.5
C) +0.83
D) -0.83
Answer: A
60. A study of the net sales of a sample of small corporations revealed that the mean net sales is $2.1
million, the median $2.4 million, the modal sales $2.6 million and the standard deviation of the
distribution is $500,000. What is the Pearson's coefficient of skewness?
A) -9.1
B) +6.3
C) -3.9
D) +2.4
E) None of the above
Answer: E
Fill-in-the-Blank
64. For a stem-and-leaf display, what is the stem for the value 67? ____.
Answer: 6
Essay
29 32 37 34 38 22
33 57 21 65 35 52
46 35 54 26 55 59
22 30 38 39 31 20
69 19 58 42 50 51
Answer:
1| 9
2| 0 1 2 2 6 9
3| 0 1 2 3 4 5 5 7 8 8 9
4| 2 6
5| 0 1 2 4 5 7 8 9
6| 5 9
66. From the following stem-and-leaf display, find the minimum value, the 1st quartile, the median, the
3rd quartile, and the maximum value. List and interpret the interquartile range.
1| 9
2| 0 1 2 2 6 9
3| 0 1 2 3 4 5 5 7 8 8 9
4| 2 6
5| 0 1 2 4 5 7 8 9
6| 5 9
Fill-in-the-Blank
67. For a stem-and-leaf display, what is the leaf for the value 123? ____.
Answer: 3
68. If you are constructing a stem-and-leaf display, the "3" in 19.3 would be the ____________.
Answer: leaf
69. If you are constructing a stem-and-leaf display, the "20" in 20.5 would be the _____________.
Answer: stem
71. What is the main advantage of a stem-and-leaf chart over a histogram? ___________________
Answer: The identity of each observation is not lost
76. If the mean of a distribution is smaller than the median and mode, what is the sign of Pearson's
coefficient of skewness? _______________
Answer: negative
78. For a set of data, how many quartiles are there? _____
Answer: three
79. If two sets of data are measured in different units, what statistic can be used to compare their
dispersions? ___________________________________
Answer: coefficient of variation
80. What unit of measurement is used to express the coefficient of variation? _________
Answer: percent
82. The research director of a large oil company conducted a study of the buying habits of consumers
with respect to the amount of gasoline purchased at full-service pumps. The arithmetic mean amount is
11.5 gallons and the median amount is 11.95 gallons. The standard deviation of the sample is 4.5 gallons.
What is the Pearson's coefficient of skewness? ________
Answer: -0.30
84. The annual incomes of the five vice presidents of Elly's Industries are: $41,000, $38,000, $32,000,
$33,000 and $50,000. The annual incomes of Unique, another firm similar to Elly's Industries, were also
studied and found to have a mean of $38,900 and a standard deviation of $6,612. What company has the
greater coefficient of variation? ______________
Answer: Elly, (19.0) > Unique (17.0)
86. The lengths of stay on the cancer floor of Community Hospital were organized into a frequency
distribution. The mean length was 28 days, the median 25 days and the modal length 23 days. The
87. A sample of the homes currently offered for sale revealed that the mean asking price is $75,900, the
median $70,100 and the modal price is $67,200. The standard deviation of the distribution is $5,900.
What is the Pearson's coefficient of skewness? __________
Answer: 2.95
88. The Pearson's coefficient of skewness (Sk) measures the amount of skewness and may range from -
3.0 to +3.0. It is computed by subtracting the median from the mean, multiplying the result by 3 and
dividing by? ________________
Answer: standard deviation
Essay
89. Given the sample information in the following table regarding public opinion on gun control, who is
more likely to favor gun control?
Answer: Republicans are more likely to favor gun control with 58% favoring gun control. Only 38% of
democrats favor gun control.
Fill-in-the-Blank
9 5 2 6 5 6 4 4 4 7
4 4 7 8 4 4 5 5 4 8
90. What is the median for the distribution of number of sales per hour? ____________
Answer: Median = 5 sales per hour
91. What is the first quartile for the distribution of number of sales per hour? ________________
Answer: Q1 = 4 sales per hour
92. What is the third quartile for the distribution of number of sales per hour? _____________
Answer: Q3 = 6.5 sales per hour
93. For the distribution of number of sales per hour, 50% are greater than ____________
Answer: The median or 5 sales per hour
11| 1 5 9
12| 0 1 2 2 6 9
13| 0 1 2 3 4 5 5 7 8 8 9
14| 2 6 8
15| 0 1 2 4 5 7 8 9
16| 1 5 7 9
99. How often did the company complete 111 shipments? ____________
Answer: 1 or once
100. How often did the company complete more than 140 shipments? __________
Answer: 15 times
Essay
102. What is the common purpose of a scatter diagram and a contingency table?
Answer: Both are used to summarize two variables:
103. What is the difference between a scatter diagram and a contingency table?
Answer: A scatter diagram requires interval or ratio scaled variables, a contingency table requires
nominal or ordinal variables.