In the following multiple-choice questions, circle the correct answer.
1. An example of statistical inference is
a. a population mean
b. descriptive statistics
c. calculating the size of a sample
d. hypothesis testing
ANSWER: d
2. In hypothesis testing, the hypothesis tentatively assumed to be true is
a. the alternative hypothesis
b. the null hypothesis
c. either the null or the alternative
d. None of the other answers are correct.
ANSWER: b
3. In hypothesis testing, the alternative hypothesis is
a. the hypothesis tentatively assumed true in the hypothesis-testing procedure
b. the hypothesis concluded to be true if the null hypothesis is rejected
c. the maximum probability of a Type I error
d. All of the answers are correct.
ANSWER: b
4. Your investment executive claims that the average yearly rate of return on the stocks she
recommends is at least 10.0%. You plan on taking a sample to test her claim. The
correct set of hypotheses is
a. H0: < 10.0% Ha: 10.0%
b. H0: 10.0% Ha: > 10.0%
c. H0: > 10.0% Ha: 10.0%
d. H0: 10.0% Ha: < 10.0%
ANSWER: d
5. A meteorologist stated that the average temperature during July in Chattanooga was 80
degrees. A sample of 32 Julys was taken. The correct set of hypotheses is
a. H0: < 80 Ha: 80
b. H0: 80 Ha: > 80
c. H0: 80 Ha: = 80
d. None of the other answers are correct.
ANSWER: d
6. A student believes that the average grade on the final examination in statistics is at least
MBS3 TB09 - 2
85. She plans on taking a sample to test her belief. The correct set of hypotheses is
a. H0: < 85 Ha: 85
b. H0: 85 Ha: > 85
c. H0: 85 Ha: < 85
d. None of the other answers are correct.
ANSWER: c
7. The average life expectancy of tires produced by the Whitney Tire Company has been
40,000 miles. Management believes that due to a new production process, the life
expectancy of its tires has increased. In order to test the validity of this belief, the
correct set of hypotheses is
a. H0: < 40,000 Ha: 40,000
b. H0: 40,000 Ha: > 40,000
c. H0: > 40,000 Ha: 40,000
d. H0: 40,000 Ha: < 40,000
ANSWER: b
8. A soft drink filling machine, when in perfect adjustment, fills the bottles with 12 ounces
of soft drink. Any overfilling or underfilling results in the shutdown and readjustment of
the machine. To determine whether or not the machine is properly adjusted, the correct
set of hypotheses is
a. H0: < 12 Ha: 12
b. H0: 12 Ha: > 12
c. H0: 12 Ha: = 12
d. H0: = 12 Ha: 12
ANSWER: d
9. The manager of an automobile dealership is considering a new bonus plan in order to
increase sales. Currently, the mean sales rate per salesperson is five automobiles per
month. The correct set of hypotheses for testing the effect of the bonus plan is
a. H0: < 5 Ha: 5
b. H0: 5 Ha: > 5
c. H0: > 5 Ha: 5
d. H0: 5 Ha: < 5
ANSWER: b
10. In hypothesis testing if the null hypothesis is rejected,
a. no conclusions can be drawn from the test
b. the alternative hypothesis must also be rejected
c. the data must have been accumulated incorrectly
d. None of the other answers are correct.
ANSWER: d
11. If a hypothesis test leads to the rejection of the null hypothesis, a
a. Type II error must have been committed
b. Type II error may have been committed
c. Type I error must have been committed
d. Type I error may have been committed
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