INSTRUCTOR ANSWER GUIDE
OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
,OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
CHAPTER 10: HYPOTHESIS TESTING WITH TWO SAMPLES
Exercise 1. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
It is believed that 70% of men pass their drivers test in the first attempt, while 65%
of women pass the test in the first attempt. Of interest is whether the proportions
are in fact equal.
Solution two proportions
Exercise 2. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
A new laundry detergent is tested on consumers. Of interest is the proportion of
consumers who prefer the new brand over the leading competitor. A study is done
to test this.
Solution single proportion
Exercise 3. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
A new windshield treatment claims to repel water more effectively. Ten
windshields are tested by simulating rain without the new treatment. The same
windshields are then treated, and the experiment is run again. A hypothesis test is
conducted.
2
October 28, 2025
,OpenStax Introductory Business Statistics 2e
Instructor Answer and Solution Guide
Chapter 10: Hypothesis Testing with Two Samples
Solution matched or paired samples
Exercise 4. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
The known standard deviation in salary for all mid-level professionals in the
financial industry is $11,000. Company A and Company B are in the financial
industry. Suppose samples are taken of mid-level professionals from Company A
and from Company B. The sample mean salary for mid-level professionals in
Company A is $80,000. The sample mean salary for mid-level professionals in
Company B is $96,000. Company A and Company B management want to know if
their mid-level professionals are paid differently, on average.
Solution independent group means, population standard deviations and/or variances known
Exercise 5. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
The average worker in Germany gets eight weeks of paid vacation.
Solution single mean
Exercise 6. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
According to a television commercial, 80% of dentists agree that Ultrafresh
3
October 28, 2025
, OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
toothpaste is the best on the market.
Solution single proportion
Exercise 7. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
It is believed that the average grade on an English essay in a particular school
system for women is higher than for men. A random sample of 31 women had a
mean score of 82 with a standard deviation of three, and a random sample of 25
men had a mean score of 76 with a standard deviation of four.
Solution independent group means, population standard deviations and/or variances
unknown
Exercise 8. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
The league mean batting average is 0.280 with a known standard deviation of
0.06. The Rattlers and the Vikings belong to the league. The mean batting average
for a sample of eight Rattlers is 0.210, and the mean batting average for a sample
of eight Vikings is 0.260. There are 24 players on the Rattlers and 19 players on
the Vikings. Are the batting averages of the Rattlers and Vikings statistically
different?
Solution independent group means, population standard deviations and/or variances known
Exercise 9. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
4
October 28, 2025
OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
,OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
CHAPTER 10: HYPOTHESIS TESTING WITH TWO SAMPLES
Exercise 1. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
It is believed that 70% of men pass their drivers test in the first attempt, while 65%
of women pass the test in the first attempt. Of interest is whether the proportions
are in fact equal.
Solution two proportions
Exercise 2. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
A new laundry detergent is tested on consumers. Of interest is the proportion of
consumers who prefer the new brand over the leading competitor. A study is done
to test this.
Solution single proportion
Exercise 3. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
A new windshield treatment claims to repel water more effectively. Ten
windshields are tested by simulating rain without the new treatment. The same
windshields are then treated, and the experiment is run again. A hypothesis test is
conducted.
2
October 28, 2025
,OpenStax Introductory Business Statistics 2e
Instructor Answer and Solution Guide
Chapter 10: Hypothesis Testing with Two Samples
Solution matched or paired samples
Exercise 4. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
The known standard deviation in salary for all mid-level professionals in the
financial industry is $11,000. Company A and Company B are in the financial
industry. Suppose samples are taken of mid-level professionals from Company A
and from Company B. The sample mean salary for mid-level professionals in
Company A is $80,000. The sample mean salary for mid-level professionals in
Company B is $96,000. Company A and Company B management want to know if
their mid-level professionals are paid differently, on average.
Solution independent group means, population standard deviations and/or variances known
Exercise 5. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
The average worker in Germany gets eight weeks of paid vacation.
Solution single mean
Exercise 6. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
According to a television commercial, 80% of dentists agree that Ultrafresh
3
October 28, 2025
, OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
toothpaste is the best on the market.
Solution single proportion
Exercise 7. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
It is believed that the average grade on an English essay in a particular school
system for women is higher than for men. A random sample of 31 women had a
mean score of 82 with a standard deviation of three, and a random sample of 25
men had a mean score of 76 with a standard deviation of four.
Solution independent group means, population standard deviations and/or variances
unknown
Exercise 8. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
c. matched or paired samples
d. single mean
e. two proportions
f. single proportion
The league mean batting average is 0.280 with a known standard deviation of
0.06. The Rattlers and the Vikings belong to the league. The mean batting average
for a sample of eight Rattlers is 0.210, and the mean batting average for a sample
of eight Vikings is 0.260. There are 24 players on the Rattlers and 19 players on
the Vikings. Are the batting averages of the Rattlers and Vikings statistically
different?
Solution independent group means, population standard deviations and/or variances known
Exercise 9. Indicate if the hypothesis test is for
a. independent group means, population standard deviations, and/or variances
known
b. independent group means, population standard deviations, and/or variances
unknown
4
October 28, 2025
