SOLUTIONS MANUAL Applied Statistics in Business and
Economics 7th Edition
Chapter 1 : Overview of Statistics
1.1 a. Statistics can be used to 1) determine what a typical commission is and then 2) use that
value to identify commissions that appear to be unusually high.
b. She could use statistics to show the average energy use compared to previous models.
She could also use statistics to show how durable the monitor would be in the field.
c. He could use statistics to calculate the average absenteeism at each plant and then
compare across the three plants.
d. He could calculate average number of defects in each shipment. He could determine
variation in number of defects between the three shipments.
Learning Objective: 01-1
1.2 a. He could calculate the job turnover for each gender for each restaurant. He could then
look at the difference between the various restaurants as well as the difference between
genders.
b. He could calculate the average number of emails received and sent for employees in
different job classifications and make comparisons.
c. The portfolio manager could calculate both the average return and the variation on return
for the six different investments and make comparisons.
d. By studying the busiest times of day for surgery, the administrator could work with
surgeons to spread their surgeries out to better use the facilities. He might also look at
which surgeries take the longest and which are shorter to help with scheduling.
Learning Objective: 01-1
1.3 a. The average business school graduate should expect to use computers to manipulate the
data.
b. Answers will vary. Weak quantitative skills lead to poor decision making because data-
based decision making is a hallmark of successful businesses. If one cannot analyze
data or understand summary analyses, one will be making decisions without full
information.
Learning Objective: 01-2
1.4 a. Answers will vary. Why Not Study: It is difficult to become a statistical “expert” after
taking one introductory college course. A business person should hire statistical experts
and have faith that those who are using statistics are doing it correctly. Why Study: In
fact, most college graduates will use statistics every day. Relying on a consultant to
perform simple or even complex statistical analyses means turning over part of the
business decision-making to someone who doesn’t know your business as well as you
do.
b. Answers will vary. Answers provided in part a will be similar for the subjects of
accounting. Foreign languages are essential in this global business environment of
today. While learning a foreign language can take considerably more time as an adult,
the investment is worth it. Businesses are looking for college graduates that have
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, quantitative skills and speak a foreign language. Chinese and Spanish are popular
choices.
c. To arrive at an absurd result, and then conclude the original assumption must have been
wrong, since it gave us this absurd result. This is also known as proof by contradiction.
It makes use of the law of excluded middle — a statement which cannot be false, must
then be true. If you state that you will never use statistics in your business profession
then you might conclude that you shouldn’t study statistics. However, the original
assumption of never using statistics is wrong; therefore the conclusion of not needing to
study statistics is also wrong.
Learning Objective: 01-2
1.5 a. Answers will vary.
b. An hour with an expert at the beginning of a project could be the smartest move a
manager can make. A consultant is helpful when your team lacks certain critical skills,
or when an unbiased or informed view cannot be found inside your organization.
Expert consultants can handle domineering or indecisive team members, personality
clashes, fears about adverse findings, and local politics. As in any business decision, the
costs of paying for statistical assistance must be weighed against the benefits. Costs
are: statistician’s time, more time invested in the beginning of a project which may
mean results are not immediate. Benefits include: better sampling strategies which can
result in more useful data, a better understanding of what information can be extracted
from the data, greater confidence in the results.
Learning Objective: 01-2
1.6 a. The ethical issue is that credit card companies are using unfair marketing practices to
entice students to use credit cards. Students are a vulnerable group that has not been
educated about personal finance. Credit card companies are also purchasing student
lists from universities and various student groups. This is also an unethical practice by
the universities.
b. They used an in-person survey given to 1500 students. These students were randomly
solicited at popular places on campus. The sampling technique was a convenience
sample. The report did not attempt to make inferences about the population of college
students. The report simply provided statistics collected from their sample. The naïve
reader would most likely make the inference that the numbers from the sample apply to
the population as a whole. This should be made clearer in the report.
c. The subjects surveyed include 1) how students pay for their education, 2) how they use
credit cards, 3) how many of them use credit cards, and 4) attitudes toward credit card
marketing on campus. It would be interesting to see what the questions were and how
they were worded.
d. Because the survey focused on students’ opinions and did not provide information about
credit card use by the general population it is difficult to conclude that the marketing
practices companies use on campuses are different from those used to market cards to
the general public. Furthermore, it was not obvious that those students who had credit
cards obtained those cards as a direct result of the campus marketing efforts. What was
impressive was the amount of research the group did to support their claims of
unethical practices. The references to other reports and court cases were a better
support for their claims in question 1.
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, e. Answers vary. In general, because the study was based on a convenience sample the
results cannot be assumed to hold for the general population of students. Also, it would
be good to know how students’ use of credit cards compares to the general public.
f. The list of schools included in the survey is focused in a few states such as
Massachusetts, California, and Colorado. There were very few schools from the
southeast and virtually no private colleges or universities. Because it was a convenience
sample it is not appropriate to extend the results from the survey to the larger
population of college students. However, many of the references cited did suggest that
the problem was widespread.
g. First, they suggest eliminating "freebies" or gifts that would entice students to sign up
for a credit card. Second, they suggest limiting posted marketing materials on campus.
The third solution is to disallow acquisition of students’ lists. Fourth, they suggest that
sponsorship should be discontinued. In other words, credit card companies cannot pay
for student groups to get them new customers. The fifth recommendation is to enhance
student awareness about credit card problems. Finally, they suggest that certain terms
that take advantage of students should be discouraged. For example, hidden fees,
changing contracts, and universal default should be eliminated.
As a follow up to this report note that the Credit Card Accountability Responsibility and
Disclosure Act of 2009 or Credit CARD Act of 2009 is a federal law passed by the
United States Congress and signed by President Barack Obama on May 22, 2009. It is
comprehensive credit card reform legislation that aims "...to establish fair and
transparent practices relating to the extension of credit under an open end consumer
credit plan, and for other purposes."[1]
Learning Objective: 01-3
1.7 Answers will vary. Examples include: linking expectations on conduct to the company’s
mission, explaining what is considered acceptable and unacceptable behavior,
providing courses of action for employees when they have questions or believe an
ethical guideline has been violated, documentation so that employees will know the
code, addressing nepotism, addressing romantic relationships, addressing customer
relationships and vendor relationships.
Learning Objective: 01-3
1.8 Mary is falling for Pitfall 3: Conclusions from Rare Events. Just because an event is
unlikely doesn’t mean it will never happen. The probability may be small but there is a
chance of observing the same five winning numbers in the same sequence on two
different days.
Learning Objective: 01-4
1.9 Bob is falling for Pitfall 5: Assuming a Causal Link. Statistical association does not prove
causation. Bob also appears to be falling for Pitfall 6: Generalization to Individuals.
Even if there were a link between cell phones and binge drinking, the link would be
between groups of cell phone users and groups of binge drinkers, not necessarily a one
to one link.
Learning Objective: 01-4
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, 1.10 a. It is not obvious that there is a direct cause and effect relationship between an individual
choosing to use a radar detector and that individual choosing to vote and wear a
seatbelt.
b. Increasing the use of radar detectors may not influence those who obey laws and are less
concerned with government limitations.
Learning Objective: 01-4
1.11 a. No, the method did not “work” in the sense that he increased his chances of winning by
picking the numbers the way he did. Every combination of six numbers has the same
chance of winning. The fact that this winner chose his numbers based on his families’
birthdays and school grade does not increase the chance of him winning.
b. Someone who picks 1-2-3-4-5-6 has just as much chance of winning as anyone else (see
(a)).
Learning Objective: 01-4
1.12 a. The phrase “much more” is not quantified. The study report is not mentioned. There is
no way to determine the veracity of this statement. Six causes of car accidents could be
poor weather, road construction, heavy traffic, inexperienced driver, engine failure, and
drinking. Smoking is not on this list.
b. Smokers might pay less attention to driving when lighting a cigarette.
Learning Objective: 01-4
1.13 The percent reduction might not seem important because it appears so small but when
multiplied by millions of calls each day it does translate into a significant improvement.
Learning Objective: 01-4
1.14 a. The conclusion was a broad generalization. This can cause ethical issues if action was
taken against employees that had legitimate complaints about management decisions.
b. The sample is too small, and non-random, creating bias.
c. This test is only going to be performed in the laboratory which limits the ability to see
how it works out in the world. Additionally, there is no informed consent.
d. The sample is once again way too small and is non random. This again creates bias
which creates no causal link.
Learning Objective: 01-4
1.15 Sarah’s statement is not correct. Most people would feel the difference is practically
important. 0.9% of 231,164 is 2,080 patients.
Learning Objective: 01-4
1.16 The headline implies causation but we cannot assume causation just because the repeal
came before the increase in deaths. The deaths could have been going up each year
before this study or there could be other variables contributing to the increase in deaths.
Although the research accounts for some third variables such as increased registrations,
it does not prove causality.
Learning Objective: 01-4
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