Question 1

In its standard form, Chebyshev's theorem provides a lower bound on ________.

Accepted Answer

A)  the number of observations lying within a certain interval 
B)  the number of observations lying outside a certain interval 
C)  the proportion (or percentage) of observations lying within a certain interval 
D)  the proportion (or percentage) of observations lying outside a certain interval

Question 2

Is it possible for a data set to have more than one mode?

Accepted Answer

A)  No, there must always be a single mode, or else there is no mode. 
B)  Yes, if two or more values in a data set occur the same number of times. 
C)  Yes, if there are at least two different values in a data set, there is always more than one mode. 
D)  Yes, if two or more values in a data set occur with the most frequency and the frequency is greater than one.

Question 3

Professors at a local university earn an average salary of $80,000 with a standard deviation of $6,000. The salary distribution is approximately bell-shaped. What can be said about the percentage of salaries that are at least $74,000?

Accepted Answer

A)  It is about 68%. 
B)  It is about 84%. 
C)  It is about 95%. 
D)  It is about 97.5%.

Question 4

As of September 30, the earnings per share (EPS) of five firms in the biotechnology industry are  (See the Excel Data File.) The sample mean and the sample standard deviation are the closest to ________.

Accepted Answer

A)  1.53 and 0.76 
B)  1.53 and 0.87 
C)  1.69 and 0.76 
D)  1.69 and 0.87

Question 5

The z-score has no units even though the original values will normally be expressed in units such as dollars, years, pounds, or calories.

Accepted Answer

A) True 
 B)False

Question 6

The following frequency distribution represents the number of hours studied per week by a sample of 50 students.  (See the Excel Data File.) The mean number of hours studied is ________.

Accepted Answer

A)  7 
B)  8 
C)  22.8 
D)  480

Question 7

The mean starting salary of recent business graduates at a university is $52,000 with a standard deviation of $16,000. The distribution of starting salaries is assumed to be symmetric and bell-shaped.
A) What proportion of business graduates has a starting salary between $20,000 and $84,000.
B) Suppose 600 business graduates from this university got hired. How many of them started with a salary between $20,000 and $84,000?

Accepted Answer

The answer of The mean starting salary of recent business...

Question 8

The following data represent the wait time, in minutes, for customers calling Dell technical support.  (See the Excel Data File.) The upper limit for determining outliers for a box-and-whisker plot is ________.

Accepted Answer

A)  29.5 minutes 
B)  31 minutes 
C)  33.5 minutes 
D)  36 minutes

Question 9

The empirical rule is only applicable for approximately bell-shaped data.

Accepted Answer

A) True 
 B)False

Question 10

The director of graduate admissions is analyzing the relationship between scores in the GRE and student performance in graduate school, as measured by a student's GPA. The table below shows a sample of 10 students.  (See the Excel Data File.) Which of the following statements is correct?

Accepted Answer

A)  The correlation between GRE and GPA is negative and weak. 
B)  The correlation between GRE and GPA is positive and weak. 
C)  The correlation between GRE and GPA is negative and strong. 
D)  The correlation between GRE and GPA is positive and strong.

Question 11

An analyst gathered the following information about the net profit margins of companies in two industries:  Compared with the other industry, the relative dispersion of net profit margins is smaller for Industry ________.

Accepted Answer

A)  B, because it has a smaller mean deviation. 
B)  B, because it has a smaller range of variation. 
C)  A, because it has a smaller standard deviation. 
D)  A, because it has a smaller coefficient of variation.

Question 12

The Boom company has recently decided to raise the salaries of all employees by 10%. Which of the following is (are) expected to be affected by this raise?

Accepted Answer

A)  Mean and mode only 
B)  Mean and median only 
C)  Mode and median only 
D)  Mean, median, and mode

Question 13

The data show operating expenses (in millions) for British Petroleum for the years Year 1 to Year 3.  a. Use the growth rates from Year 1 − 2 and Year 2 − Year 3 to calculate the average growth rate.
B) Calculate the average growth rate directly from sales.

Accepted Answer

The answer of The data show operating expenses (in millions)...

Question 14

Amounts spent by a sample of 50 customers at a retail store are summarized in the following relative frequency distribution.  (See the Excel Data File.) The mean amount spent by customers is the closest to ________.

Accepted Answer

A)  $0.36 
B)  $18.00 
C)  $20.00 
D)  $25.00

Question 15

The mean starting salary of recent business graduates at a university is $52,000 with a standard deviation of $16,000. The distribution of starting salaries is unknown.
A) What proportion of business graduates has a starting salary between $20,000 and $84,000?
B) Suppose 600 business graduates from this university got hired. How many of them started with a salary between $20,000 and $84,000?

Accepted Answer

The answer of The mean starting salary of recent business...

Question 16

A college professor collected data on the number of hours spent by his 100 students over the weekend to prepare for Monday's Business Statistics exam. He processed the data by Excel and the following incomplete output is available.  The coefficient of variation in the data is ________.

Accepted Answer

A)  40% 
B)  90% 
C)  111% 
D)  243%

Question 17

In a data set, an outlier is a large or small value regarded as an extreme value in the data set.

Accepted Answer

A) True 
 B)False

Question 18

The geometric mean is a multiplicative average of a data set used to measure values over a period of time.

Accepted Answer

A) True 
 B)False

Question 19

The formula for a z-score is =  .

Accepted Answer

A) True 
 B)False

Question 20

Mean-variance analysis suggests that investments with lower average returns are also associated with higher risks.

Accepted Answer

A) True 
 B)False

Exam 3: Numerical Descriptive Measures

In its standard form, Chebyshev's theorem provides a lower bound on ________.

Is it possible for a data set to have more than one mode?

Professors at a local university earn an average salary of $80,000 with a standard deviation of $6,000. The salary distribution is approximately bell-shaped. What can be said about the percentage of salaries that are at least $74,000?

As of September 30, the earnings per share (EPS) of five firms in the biotechnology industry are (See the Excel Data File.) The sample mean and the sample standard deviation are the closest to ________.

The z-score has no units even though the original values will normally be expressed in units such as dollars, years, pounds, or calories.

The following frequency distribution represents the number of hours studied per week by a sample of 50 students. (See the Excel Data File.) The mean number of hours studied is ________.

The following data represent the wait time, in minutes, for customers calling Dell technical support. (See the Excel Data File.) The upper limit for determining outliers for a box-and-whisker plot is ________.

The empirical rule is only applicable for approximately bell-shaped data.

The director of graduate admissions is analyzing the relationship between scores in the GRE and student performance in graduate school, as measured by a student's GPA. The table below shows a sample of 10 students. (See the Excel Data File.) Which of the following statements is correct?

An analyst gathered the following information about the net profit margins of companies in two industries: Compared with the other industry, the relative dispersion of net profit margins is smaller for Industry ________.

The Boom company has recently decided to raise the salaries of all employees by 10%. Which of the following is (are) expected to be affected by this raise?

The data show operating expenses (in millions) for British Petroleum for the years Year 1 to Year 3. a. Use the growth rates from Year 1 − 2 and Year 2 − Year 3 to calculate the average growth rate. B) Calculate the average growth rate directly from sales.

Amounts spent by a sample of 50 customers at a retail store are summarized in the following relative frequency distribution. (See the Excel Data File.) The mean amount spent by customers is the closest to ________.

A college professor collected data on the number of hours spent by his 100 students over the weekend to prepare for Monday's Business Statistics exam. He processed the data by Excel and the following incomplete output is available. The coefficient of variation in the data is ________.

In a data set, an outlier is a large or small value regarded as an extreme value in the data set.

The geometric mean is a multiplicative average of a data set used to measure values over a period of time.

The formula for a z-score is = .

Mean-variance analysis suggests that investments with lower average returns are also associated with higher risks.