CHAPTER NINE
HYPOTHESIS TESTS
MULTIPLE-CHOICE QUESTIONS
In the following multiple-choice questions, circle the correct answer.
1. More evidence against H0 is indicated by
a. lower levels of significance
b. smaller p-values
c. smaller critical values
d. lower probabilities of a Type II error
2. Two approaches to drawing a conclusion in a hypothesis test are
a. p-value and critical value
b. one-tailed and two-tailed
c. Type I and Type II
d. null and alternative
3. As a general guideline, the research hypothesis should be stated as the
a. null hypothesis
b. alternative hypothesis
c. tentative assumption
d. hypothesis the researcher wants to disprove
4. A Type I error is committed when
a. a true alternative hypothesis is not accepted
b. a true null hypothesis is rejected
c. the critical value is greater than the value of the test statistic
d. sample data contradict the null hypothesis
5. Which of the following hypotheses applies to a situation where action must be taken both
when H0 cannot be rejected and when H0 can be rejected?
a.
00
:H
b.
00
:H
c.
00
:H
=
d.
0
:
a
H
6. The practice of concluding “do not reject H0” is preferred over “accept H0” when we
a. are conducting a one-tailed test
b. are testing the validity of a claim
EMBS4 TB09 – 2
c. have an insufficient sample size
d. have not controlled for the Type II error
7. If the cost of a Type I error is high, a smaller value should be chosen for the
a. critical value
b. confidence coefficient
c. level of significance
d. test statistic
8. When the rejection region is in the lower tail of the sampling distribution, the p-value is
the area under the curve
a. less than or equal to the critical value
b. less than or equal to the test statistic
c. greater than or equal to the critical value
d. greater than or equal to the test statistic
9. In tests about a population proportion, p0 represents the
a. hypothesized population proportion
b. observed sample proportion
c. observed p-value
d. probability of
0pp−=
10. Which of the following is an improper form of the null and alternative hypotheses?
a.
00
:H
and
00
:H
b.
00
:H
=
and
00
:H
c.
00
:H
and
00
:H
d.
00
:H
and
00
:H
11. For a two-tailed hypothesis test about
, we can use any of the following approaches
except
a. compare the confidence interval estimate of
to the hypothesized value of
b. compare the p-value to the value of
c. compare the value of the test statistic to the critical value
d. compare the level of significance to the confidence coefficient
12. An example of statistical inference is
a. a population mean
b. descriptive statistics
c. calculating the size of a sample
d. hypothesis testing
13. 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.
14. 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.
15. 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%
16. 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.
17. A student believes that the average grade on the final examination in statistics is at least
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.
18. 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
19. 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
20. 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
21. 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.
22. 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
23. The error of rejecting a true null hypothesis is
a. a Type I error
b. a Type II error
c. can be either a or b, depending on the situation
d. committed when not enough information is available
24. In hypothesis testing if the null hypothesis has been rejected when the alternative
hypothesis has been true,
a. a Type I error has been committed
b. a Type II error has been committed
c. either a Type I or Type II error has been committed
d. the correct decision has been made
25. A Type II error is committed when
a. a true alternative hypothesis is mistakenly rejected
b. a true null hypothesis is mistakenly rejected
c. the sample size has been too small
d. not enough information has been available
26. The probability of making a Type I error is denoted by
a.
b.
c. 1 –
d. 1 –
27. The level of significance is the
a. maximum allowable probability of Type II error
b. maximum allowable probability of Type I error
c. same as the confidence coefficient
d. same as the p-value
28. The level of significance in hypothesis testing is the probability of
a. accepting a true null hypothesis
b. accepting a false null hypothesis
c. rejecting a true null hypothesis
d. could be any of the above, depending on the situation
29. In the hypothesis testing procedure, is
a. the level of significance
b. the critical value
c. the confidence level
d. 1 − level of significance
30. The level of significance can be any
a. negative value
b. value
c. value larger than 0.1
d. None of the answers is correct.
31. The probability of making a Type II error is denoted by
a.
b.
c. 1 –
d. 1 –
32. The probability of rejecting a false null hypothesis is equal to
a. 1 –
b. 1 –
c.
d.
33. If the level of significance of a hypothesis test is raised from .01 to .05, the probability of
a Type II error
a. will also increase from .01 to .05
b. will not change
c. will decrease
d. Not enough information is given to answer this question.
34. In hypothesis testing, the critical value is
a. a number that establishes the boundary of the rejection region
b. the probability of a Type I error
c. the probability of a Type II error
d. the same as the p-value
35. A one-tailed test is a
a. hypothesis test in which rejection region is in both tails of the sampling
distribution
b. hypothesis test in which rejection region is in one tail of the sampling distribution
c. hypothesis test in which rejection region is only in the lower tail of the sampling
distribution
d. hypothesis test in which rejection region is only in the upper tail of the sampling
distribution
36. A two-tailed test is a
a. hypothesis test in which rejection region is in both tails of the sampling
distribution
b. hypothesis test in which rejection region is in one tail of the sampling distribution
c. hypothesis test in which rejection region is only in the lower tail of the sampling
distribution
d. hypothesis test in which rejection region is only in the upper tail of the sampling
distribution
37. Read the z statistics from the normal distribution table and circle the correct answer. A
two-tailed test at a .0694 level of significance; z =
a. -1.96 and 1.96
b. -1.48 and 1.48
c. -1.09 and 1.09
d. -0.86 and 0.86
38. Read the z statistic from the normal distribution table and circle the correct answer. A
one-tailed test (lower tail) at a .063 level of significance; z =
a -1.86
b. -1.53
c. -1.96
d. -1.645
39. Read the z statistic from the normal distribution table and circle the correct answer. A
one-tailed test (upper tail) at a .123 level of significance; z =
a. 1.54
b. 1.96
c. 1.645
d. 1.16
40. When the hypotheses H0:
100 and Ha:
< 100 are being tested at a level of
significance of , the null hypothesis will be rejected if the test statistic z is
a. > z
b. > –z
c. < –z
d. < 100
41. In order to test the hypotheses H0: 100 and Ha:
> 100 at an level of significance,
the null hypothesis will be rejected if the test statistic z is
a. > z
b. < z
c. < –z
d. < 100
42. For a one-tailed test (upper tail) with a sample size of 900, the null hypothesis will be
rejected at the .05 level of significance if the test statistic is
a. less than or equal to -1.645
b. greater than or equal to 1.645
c. less than 1.645
d. less than -1.96
43. For a two-tailed test with a sample size of 40, the null hypothesis will not be rejected at a
5% level of significance if the test statistic is
a. between -1.96 and 1.96, exclusively
b. greater than 1.96
c. less than 1.645
d. greater than -1.645
44. If a hypothesis is rejected at a 5% level of significance, it
a. will always be rejected at the 1% level
b. will always be accepted at the 1% level
c. will never be tested at the 1% level
d. may be rejected or not rejected at the 1% level
45. If a hypothesis is not rejected at a 5% level of significance, it will
a. also not be rejected at the 1% level
b. always be rejected at the 1% level
c. sometimes be rejected at the 1% level
d. Not enough information is given to answer this question.
46. A p-value is the
a. probability, when the null hypothesis is true, of obtaining a sample result that is
at least as unlikely as what is observed
b. value of the test statistic
c. probability of a Type II error
d. probability corresponding to the critical value(s) in a hypothesis test
47. Which of the following does not need to be known in order to compute the p-value?
a. knowledge of whether the test is one-tailed or two-tailed
b. the value of the test statistic
c. the level of significance
d. All of these are needed.
48. When the p-value is used for hypothesis testing, the null hypothesis is rejected if
a. p-value <
b. < p-value
c. p-value >
d. p-value = z
Exhibit 9-1
n = 36
H0:
20
x
= 24.6
Ha:
> 20
= 12
49. Refer to Exhibit 9-1. The test statistic equals
a. 2.3
b. 0.38
c. -2.3
d. -0.38
50. Refer to Exhibit 9-1. The p–value is
a. 0.5107
b. 0.0214
c. 0.0107
d. 2.1
51. Refer to Exhibit 9-1. If the test is done at a .05 level of significance, the null hypothesis
should
a. not be rejected
b. be rejected
c. Not enough information is given to answer this question.
d. None of the other answers are correct.
Exhibit 9-2
The manager of a grocery store has taken a random sample of 100 customers. The average length
of time it took the customers in the sample to check out was 3.1 minutes. The population
standard deviation is known to be 0.5 minutes. We want to test to determine whether or not the
mean waiting time of all customers is significantly more than 3 minutes.
52. Refer to Exhibit 9-2. The test statistic is
a. 1.96
b. 1.64
c. 2.00
d. 0.056
53. Refer to Exhibit 9-2. The p–value is
a. 0.025
b. 0.0456
c. 0.05
d. 0.0228
54. Refer to Exhibit 9-2. At a .05 level of significance, it can be concluded that the mean of
the population is
a. significantly greater than 3
b. not significantly greater than 3
c. significantly less than 3
d. significantly greater then 3.18
Exhibit 9-3
n = 49
H0:
= 50
x
= 54.8
Ha:
50
= 28
55. Refer to Exhibit 9-3. The test statistic equals
a. 0.1714
b. 0.3849
c. -1.2
d. 1.2
56. Refer to Exhibit 9-3. The p–value is equal to
a. 0.1151
b. 0.3849
c. 0.2698
d. 0.2302
57. Refer to Exhibit 9-3. If the test is done at a 5% level of significance, the null hypothesis
should
a. not be rejected
b. be rejected
c. Not enough information given to answer this question.
d. None of the other answers are correct.
58. A two-tailed test is performed at a 5% level of significance. The p-value is determined to
be 0.09. The null hypothesis
a. must be rejected
b. should not be rejected
c. may or may not be rejected, depending on the sample size.
d. has been designed incorrectly
59. Excel’s __________ function can be used to calculate a p-value for a hypothesis test.
a. RAND
b. NORMSDIST
c. NORMSINV
d. Not enough information is given to answer this question.
60. When using Excel to calculate a p–value for an upper-tail hypothesis test, the following
must be used
a. RAND
b. 1 − NORMSDIST
c. NORMSDIST
d. Not enough information is given to answer this question.
61. When using Excel to calculate a p–value for a lower-tail hypothesis test, the following
must be used
a. RAND
b. 1 − NORMSDIST
c. NORMSDIST
d. Not enough information is given to answer this question.
62. For a sample size of 30, changing from using the standard normal distribution to using
the t distribution in a hypothesis test,
a. will result in the rejection region being smaller
b. will result in the rejection region being larger
c. would have no effect on the rejection region
d. Not enough information is given to answer this question.
63. Read the t statistic from the table of t distributions and circle the correct answer. A two-
tailed test, a sample of 20 at a .20 level of significance; t =
a. 1.328
b. 2.539
c. 1.325
d. 2.528
64. Read the t statistic from the table of t distributions and circle the correct answer. A one–
tailed test (upper tail), a sample size of 18 at a .05 level of significance t =
a. 2.12
b. 1.734
c. -1.740
d. 1.740
65. Read the t statistic from the table of t distributions and circle the correct answer. A one–
tailed test (lower tail), a sample size of 10 at a .10 level of significance; t =
a. 1.383
b. -1.372
c. -1.383
d. -2.821
Exhibit 9-4
A random sample of 16 students selected from the student body of a large university had an
average age of 25 years. We want to determine if the average age of all the students at the
university is significantly different from 24. Assume the distribution of the population of ages is
normal with a standard deviation of 2 years.
66. Refer to Exhibit 9-4. The test statistic is
a. 1.96
b. 2.00
c. 1.645
d. 0.05
67. Refer to Exhibit 9-4. At a .05 level of significance, it can be concluded that the mean age
is
a. not significantly different from 24
b. significantly different from 24
c. significantly less than 24
d. significantly less than 25
Exhibit 9-5
n = 16
H0:
80
x
= 75.607
Ha:
< 80
= 8.246
Assume population is normally distributed.
68. Refer to Exhibit 9-5. The test statistic equals
a. -2.131
b. -0.53
c. 0.53
d. 2.131
69. Refer to Exhibit 9-5. The p–value is equal to
a. -0.0166
b. 0.0166
c. 0.0332
d. 0.9834
70. Refer to Exhibit 9-5. If the test is done at a 2% level of significance, the null hypothesis
should
a. not be rejected
b. be rejected
c. Not enough information is given to answer this question.
d. None of the other answers are correct.
71. Excel’s __________ function can be used to calculate a p-value for a hypothesis test
when is unknown.
a. RAND
b. TDIST
c. NORMSDIST
d. Not enough information is given to answer this question.
72. The school’s newspaper reported that the proportion of students majoring in business is at
least 30%. You plan on taking a sample to test the newspaper’s claim. The correct set of
hypotheses is
a. H0: p < 0.30 Ha: p 0.30
b. H0: p 0.30 Ha: p > 0.30
c. H0: p 0.30 Ha: p < 0.30
d. H0: p > 0.30 Ha: p 0.30
73. In the past, 75% of the tourists who visited Chattanooga went to see Rock City. The
management of Rock City recently undertook an extensive promotional campaign. They
are interested in determining whether the promotional campaign actually increased the
proportion of tourists visiting Rock City. The correct set of hypotheses is
a. H0: p > 0.75 Ha: p 0.75
b. H0: p < 0.75 Ha: p 0.75
c. H0: p 0.75 Ha: p < 0.75
d. H0: p 0.75 Ha: p > 0.75
74. The academic planner of a university thinks that at least 35% of the entire student body
attends summer school. The correct set of hypotheses to test his belief is
a. H0: p > 0.35 Ha: p 0.35
b. H0: p 0.35 Ha: p > 0.35
c. H0: p 0.35 Ha: p < 0.35
d. H0: p > 0.35 Ha: p 0.35
Exhibit 9-6
A random sample of 100 people was taken. Eighty of the people in the sample favored Candidate
A. We are interested in determining whether or not the proportion of the population in favor of
Candidate A is significantly more than 75%.
75. Refer to Exhibit 9-6. The test statistic is
a. 0.80
b. 0.05
c. 1.25
d. 2.00
76. Refer to Exhibit 9-6. The p–value is
a. 0.2112
b. 0.05
c. 0.025
d. 0.0156
77. Refer to Exhibit 9-6. At a .05 level of significance, it can be concluded that the
proportion of the population in favor of candidate A is
a. significantly greater than 75%
b. not significantly greater than 75%
c. significantly greater than 80%
d. not significantly greater than 80%
78. Which Excel function would not be appropriate to use when conducting a hypothesis test
for a population proportion?
a. NORMSDIST
b. COUNTIF
c. STDEV
d. All are appropriate.
PROBLEMS
1. A researcher is testing a new painkiller that claims to relieve pain in less than 15 minutes,
on average.
a. State the hypotheses associated with the researcher’s test.
b. Describe a Type I error for this situation.
c. Describe a Type II error for this situation.