The coefficient of variation for a set of annual incomes is 18%; the coefficient of variation for
the length of service with the company is 29%. What does this indicate?
A) More dispersion in the distribution of the incomes compared with the dispersion of

Module 4 Homework 1
Running head: Module 4 Homework
Module 4 Homework
Leah Cummings
Allied American University
Author Note
This paper was prepared for ECN 150, Module 4 Homework taught by Professor Danielle
Babb.
PART I
1.
For each of the following, deter

For a distribution, the 2nd quartile, the 5th decile, and the 50th percentile, are the same as the
median.
Answer: True
21. The interquartile range is the difference between the values of the first and third quartile,
indicating the range of the middle fi

Chapter 4
Describing Data: Displaying and Exploring Data
A student scored in the 85th percentile on a standardized test. This means that the student
scored lower than 85% of all students who took the test.
Answer: False
15. Quartiles are another way to de

In a contingency table, we describe the relationship between
A) two variables measured at the ordinal or nominal level.
B) two variables, one measured as an ordinal variable and the other as a ratio variable
C) two variables measured at the interval or ra

A scatter diagram of sales versus production may be constructed by plotting the data on a
graph labeled with sales on the Y-axis and production on the X-axis.
Answer: True
42. A relationship between gender and preference for Coke or Pepsi can be best repr

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

In a scatter diagram, we describe the relationship between
A) two variables measured at the ordinal level
B) two variables, one measured as an ordinal variable and the other as a ratio variable
C) two variables measured at the interval or ratio level
D) a

What is the best way to display the relationship between two variables measured on an
interval or ratio level?
Answer: scatter diagram
71. What is the main advantage of a stem-and-leaf chart over a histogram?
_
Answer: The identity of each observation is

Fill-in-the-Blank
What chart or graph is useful for illustrating frequencies?
_.
Answer: dot plot
64. For a stem-and-leaf display, what is the stem for the value 67? _.
Answer: 6
Difficulty: Easy
Goal: 2
Essay
65. Construct a stem-and-leaf display for the

What does the interquartile range describe?
A) The lower 50% of the observations
B) The middle 50% of the observations
C) The upper 50% of the observations
D) The lower 25% and the upper 25% of the observations
E) None of the above
Answer: B
50. The coeff

The Pearson's coefficient of skewness is a measure of distribution's symmetry.
Answer: True
33. The coefficient of variation is useful for comparing distributions with different units.
Answer: True
Difficulty: Easy
Goal: 5
34. The coefficient of variation

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
47. What statistics are needed to draw a box plot?
A) Minimum, maximum, median, first

The spread in the annual prices of stocks selling under $10 and those selling over $60 are to
be compared. The mean price of the stocks selling under $10 is $5.25 and the standard
deviation is $1.52. The mean price of those stocks selling over $60 is $92.

.
What are the smallest and largest values?_
Answer: 111 and 169 orders
98. List the actual values in the fourth class._
Answer: 142, 146, and 148 orders
Difficulty: Easy
Goal 2
99. How often did the company complete 111 shipments? _
Answer: 1 or once
Dif

Chapter 4
Describing Data: Displaying and Exploring Data
The stem in a stem-and-leaf display is the leading digit.
Answer: True
8. In a stem-and-leaf display, the leaf represents a class of a frequency distribution.
Answer: False
Difficulty: Easy
Goal: 2

.
What is the common purpose of a scatter diagram and a contingency table?
Answer: Both are used to summarize two variables:
Difficulty: Medium
Goal: 6, 7
103. What is the difference between a scatter diagram and a contingency table?
Answer: A scatter dia

.
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
Difficulty: Medium
Goal: 4
93

.
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
Difficulty: Medium
Goal: 4
92. What

.
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
Difficulty: Medium
Goal: 4

What is the main advantage of a stem-and-leaf chart over a histogram?
_
Answer: The identity of each observation is not lost
72. The percentile range is the distance between any two _.
Answer: percentiles
Difficulty: Medium
Goal: 3
73. In a symmetric dist

Chapter 4
Describing Data: Displaying and Exploring Data
There is some loss of information when raw data is tallied into a stem-and-leaf display.
Answer: False
6. For a stem-and-leaf display, the leaf for the value 98 is 9.
Answer: False
Difficulty: Easy

What is the possible range of values for the coefficient of variation?
A) -1 and +1
B) -3 and +3
C) 0% and 100%
D) Unlimited values
Answer: C
56. A research analyst wants to compare the dispersion in the price-to-earnings ratios
for a group of common stoc

.
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.
104. Draw a negatively or positively skewed distr

Chapter 4
Describing Data: Displaying and Exploring Data
In a stem-and-leaf display, it is easy to find the range for a data set.
Answer: True
12. Quartiles divide a distribution into four equal parts.
Answer: True
Difficulty: Easy
Goal: 3
13. A percentil

What statistics are needed to draw a box plot?
A) Minimum, maximum, median, first and third quartiles
B) Median, mean and standard deviation
C) A median and an interquartile range
D) A mean and a standard deviation.
Answer: A
48. A box plot shows
A) The m

The "box" in a box plot shows the interquartile range.
Answer: True
24. An outlier is a data point that occurs in the first quartile.
Answer: False
Difficulty: Easy
Goal: 4
25. An outlier is a value in a data set that is inconsistent with the rest of the

The percentile range is the distance between any two _.
Answer: percentiles
73. In a symmetric distribution, where is the 99th percentile located?
_
Answer: In the far right tail
Difficulty: Medium
Goal: 3
74. In a positively skewed distribution, where is

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

The interquartile range is the difference between the values of the first and third quartile,
indicating the range of the middle fifty percent of the observations.
Answer: True
22. A box plot graphically shows data that are in percentiles.
Answer: False
D