SOLUTIONS MANUAL
All Chapters Included
,PROBABILITY AND STATISTICS FOR ENGINEERING And THE SCIENCES 9TH EDITION
CONTENTS
Chapter 1 Overview and Descriptive Statistics 1
Chapter 2 Probability 48
Chapter 3 Discrete Random Variables and Probability 90
Distributions
Chapter 4 Continuous Random Variables and Probability 126
Distributions
Chapter 5 Joint Probability Distributions and Random Samples 177
Chapter 6 Point Estimation 206
Chapter 7 Statistical Intervals Based on a Single Sample 217
Chapter 8 Tests ofHypotheses Based on a Single Sample 234
Chapter 9 Inferences Based on Two Samples 255
Chapter 10 The Analysis ofVariance 285
Chapter 11 Multifactor Analysis ofVariance 299
Chapter 12 Simple Linear Regression and Correlation 330
Chapter 13 Nonlinear and Multiple Regression 368
Chapter 14 Goodness-of-Fit Tests and Categorical Data Analysis 406
Chapter 15 Distribution-Free Procedures 424
Chapter 16 Quality Control Methods 434
, CHAPTER 1
Section 1 .1
.
a. Los Angeles Times, Oberlin Tribune, Gainesville Sun, Washington Post
b. Duke Energy, Clorox, Seagate, Neiman Marcus
c. Vince Correa, Catherine Miller, Michael Cutler, Ken Lee
d. 2.97, 3.56, 2.20, 2.97
2.
a. 29.1 yd, 28.3 yd, 24.7 yd, 31.0 yd
b. 432 pp, 196 pp, 184 pp, 321 pp
c. 2.1, 4.0, 3.2, 6.3
d. 0.07 g, 1.58 g, 7.1 g, 27.2 g
3.
a. How likely is it that more than halfofthe sampled computers will need or have needed
warranty service? What is the expected number among the 100 that need warranty
service? How likely is it that the number needing warranty service will exceed the
expected number by more than 10?
b. Suppose that 15 ofthe 100 sampled needed warranty service. How confident can we be
that the proportion ofall such computers needing warranty service is between .08 and
.22? Does the sample provide compelling evidence for concluding that more than 10% of
all such computers need warranty service?
1
, Chapter 1: Overview and Descriptive Statistics
4.
a. Concrete populations: all living U.S. Citizens, all mutual funds marketed in the U.S., all
books published in 1980
Hypothetical populations: all grade point averages for University of California
undergraduates during the next academic year, page lengths for all books published
during the next calendar year, batting averages for all major league players during the
next baseball season
b. (Concrete) Probability: In a sample of 5 mutual funds, what is the chance that all 5 have
rates ofreturn which exceeded 10% last year?
Statistics: If previous year rates-of-return for 5 mutual funds were 9.6, 14.5, 8.3, 9.9 and
10.2, can we conclude that the average rate for all funds was below 10%?
(Hypothetical) Probability: In a sample of10 books to be published next year, how likely
is it that the average number ofpages for the 10 is between 200 and 250?
Statistics: Ifthe sample average number ofpages for 10 books is 227, can we be highly
confident that the average for all books is between 200 and 245?
9.
a. No. All students taking a large statistics course who participate in an SI program ofthis
sort.
b. The advantage to randomly allocating students to the two groups is that the two groups
should then be fairly comparable before the study. Ifthe two groups perform differently
in the class, we might attribute this to the treatments (SI and control). Ifit were left to
students to choose, stronger or more dedicated students might gravitate toward SI,
confounding the results.
c. Ifall students were put in the treatment group, there would be no firm basis for assessing
the effectiveness ofSI (nothing to which the SI scores could reasonably be compared).
6. One could take a simple random sample ofstudents from all students in the California State
University system and ask each student in the sample to report the distance form their
hometown to campus. Alternatively, the sample could be generated by taking a stratified
random sample by taking a simple random sample from each ofthe 23 campuses and again
asking each student in the sample to report the distance from their hometown to campus.
Certain problems might arise with selfreporting ofdistances, such as recording error or poor
recall. This study is enumerative because there exists a finite, identifiable population of
objects from which to sample.
7. One could generate a simple random sample ofall single-family homes in the city, or a
stratified random sample by taking a simple random sample from each ofthe 10 district
neighborhoods. From each ofthe selected homes, values ofall desired variables would be
determined. This would be an enumerative study because there exists a finite, identifiable
population ofobjects from which to sample.
2
All Chapters Included
,PROBABILITY AND STATISTICS FOR ENGINEERING And THE SCIENCES 9TH EDITION
CONTENTS
Chapter 1 Overview and Descriptive Statistics 1
Chapter 2 Probability 48
Chapter 3 Discrete Random Variables and Probability 90
Distributions
Chapter 4 Continuous Random Variables and Probability 126
Distributions
Chapter 5 Joint Probability Distributions and Random Samples 177
Chapter 6 Point Estimation 206
Chapter 7 Statistical Intervals Based on a Single Sample 217
Chapter 8 Tests ofHypotheses Based on a Single Sample 234
Chapter 9 Inferences Based on Two Samples 255
Chapter 10 The Analysis ofVariance 285
Chapter 11 Multifactor Analysis ofVariance 299
Chapter 12 Simple Linear Regression and Correlation 330
Chapter 13 Nonlinear and Multiple Regression 368
Chapter 14 Goodness-of-Fit Tests and Categorical Data Analysis 406
Chapter 15 Distribution-Free Procedures 424
Chapter 16 Quality Control Methods 434
, CHAPTER 1
Section 1 .1
.
a. Los Angeles Times, Oberlin Tribune, Gainesville Sun, Washington Post
b. Duke Energy, Clorox, Seagate, Neiman Marcus
c. Vince Correa, Catherine Miller, Michael Cutler, Ken Lee
d. 2.97, 3.56, 2.20, 2.97
2.
a. 29.1 yd, 28.3 yd, 24.7 yd, 31.0 yd
b. 432 pp, 196 pp, 184 pp, 321 pp
c. 2.1, 4.0, 3.2, 6.3
d. 0.07 g, 1.58 g, 7.1 g, 27.2 g
3.
a. How likely is it that more than halfofthe sampled computers will need or have needed
warranty service? What is the expected number among the 100 that need warranty
service? How likely is it that the number needing warranty service will exceed the
expected number by more than 10?
b. Suppose that 15 ofthe 100 sampled needed warranty service. How confident can we be
that the proportion ofall such computers needing warranty service is between .08 and
.22? Does the sample provide compelling evidence for concluding that more than 10% of
all such computers need warranty service?
1
, Chapter 1: Overview and Descriptive Statistics
4.
a. Concrete populations: all living U.S. Citizens, all mutual funds marketed in the U.S., all
books published in 1980
Hypothetical populations: all grade point averages for University of California
undergraduates during the next academic year, page lengths for all books published
during the next calendar year, batting averages for all major league players during the
next baseball season
b. (Concrete) Probability: In a sample of 5 mutual funds, what is the chance that all 5 have
rates ofreturn which exceeded 10% last year?
Statistics: If previous year rates-of-return for 5 mutual funds were 9.6, 14.5, 8.3, 9.9 and
10.2, can we conclude that the average rate for all funds was below 10%?
(Hypothetical) Probability: In a sample of10 books to be published next year, how likely
is it that the average number ofpages for the 10 is between 200 and 250?
Statistics: Ifthe sample average number ofpages for 10 books is 227, can we be highly
confident that the average for all books is between 200 and 245?
9.
a. No. All students taking a large statistics course who participate in an SI program ofthis
sort.
b. The advantage to randomly allocating students to the two groups is that the two groups
should then be fairly comparable before the study. Ifthe two groups perform differently
in the class, we might attribute this to the treatments (SI and control). Ifit were left to
students to choose, stronger or more dedicated students might gravitate toward SI,
confounding the results.
c. Ifall students were put in the treatment group, there would be no firm basis for assessing
the effectiveness ofSI (nothing to which the SI scores could reasonably be compared).
6. One could take a simple random sample ofstudents from all students in the California State
University system and ask each student in the sample to report the distance form their
hometown to campus. Alternatively, the sample could be generated by taking a stratified
random sample by taking a simple random sample from each ofthe 23 campuses and again
asking each student in the sample to report the distance from their hometown to campus.
Certain problems might arise with selfreporting ofdistances, such as recording error or poor
recall. This study is enumerative because there exists a finite, identifiable population of
objects from which to sample.
7. One could generate a simple random sample ofall single-family homes in the city, or a
stratified random sample by taking a simple random sample from each ofthe 10 district
neighborhoods. From each ofthe selected homes, values ofall desired variables would be
determined. This would be an enumerative study because there exists a finite, identifiable
population ofobjects from which to sample.
2
