CH 10 - Inference About Means and Proportions with Two Populations

Multiple Choice

1. If we are interested in testing whether the proportion of items in population 1 is larger than the proportion of items in
population 2, the

a. null hypothesis should state p1 - p2 < 0.

b. null hypothesis should state p1 - p2 > 0.

c. alternative hypothesis should state p1 - p2 > 0.

d. alternative hypothesis should state p1 - p2 < 0.

ANSWER:

c

POINTS:

1

DIFFICULTY:

Easy

LEARNING OBJECTI BSST.ASWC.17.10.04 - Inferences About the Difference Between Two
VES:
Population Proportions

NATIONAL STANDA United States - BUSPROG: Analytic
RDS:

STATE STANDARDS: United States - AK - DISC: Hypothesis Testing

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CH 10 - Inference About Means and Proportions with Two Populations

KEYWORDS:

Bloom's: Understand

2. To compute an interval estimate for the difference between the means of two populations, the t distribution

a. is restricted to small sample situations.

b. is not restricted to small sample situations.

c. can be applied when the populations have equal means.

d. can be applied only when the populations have equal standard deviations.

ANSWER:

b


POINTS:

1

DIFFICULTY:

Easy

LEARNING OBJE BSST.ASWC.17.10.02 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Unknown

NATIONAL STAN United States - BUSPROG: Analytic
DARDS:

STATE STANDARD United States - AK - DISC: Interval Estimation
S:

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CH 10 - Inference About Means and Proportions with Two Populations

KEYWORDS:

Bloom's: Understand

3. When developing an interval estimate for the difference between two population means with sample sizes of n1 and n2,


a. n1 must be equal to n2.

b. n1 must be smaller than n2.

c. n1 must be larger than n2.

d. n1 and n2 can be of different sizes.

ANSWER:

d

POINTS:

1

DIFFICULTY:

Easy

LEARNING OBJE BSST.ASWC.17.10.02 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Unknown

NATIONAL STAN United States - BUSPROG: Analytic
DARDS:

STATE STANDARD United States - AK - DISC: Interval Estimation
S:


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CH 10 - Inference About Means and Proportions with Two Populations

KEYWORDS:

Bloom's: Understand

4. To construct an interval estimate for the difference between the means of two populations when the standard deviations
of the two populations are unknown and it can be assumed the two populations have equal variances, we must use a t
distribution with (let n1 be the size of sample 1 and n2 the size of sample 2)

a. (n1 + n2) degrees of freedom.

b. (n1 + n2 - 1) degrees of freedom.

c. (n1 + n2 - 2) degrees of freedom.

d. (n1 - n2 + 2) degrees of freedom.

ANSWER:

c

POINTS:


1

DIFFICULTY:

Easy

LEARNING OBJE BSST.ASWC.17.10.02 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Unknown

NATIONAL STAN United States - BUSPROG: Analytic
DARDS:

STATE STANDARD United States - AK - DISC: Interval Estimation
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CH 10 - Inference About Means and Proportions with Two Populations

S:

KEYWORDS:

Bloom's: Remember

5. When each data value in one sample is matched with a corresponding data value in another sample, the samples are
known as


a. corresponding samples.

b. matched samples.

c. independent samples.

d. pooled samples.

ANSWER:

b

POINTS:

1

DIFFICULTY:

Easy

LEARNING OBJE BSST.ASWC.17.10.03 - Inferences About the Difference Between Two
CTIVES:
Population Means: Matched Samples

NATIONAL STAND United States - BUSPROG: Analytic
ARDS:

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CH 10 - Inference About Means and Proportions with Two Populations

STATE STANDARD United States - AK - DISC: Statistical Inference
S:

KEYWORDS:

Bloom's: Remember

6. Two independent simple random samples are taken to test the difference between the means of two populations whose
variances are not known, but are assumed to be equal. The sample sizes are n1 = 32 and n2 = 40. The correct distribution
to use is the

a. t distribution with 73 degrees of freedom.

b. t distribution with 72 degrees of freedom.

c. t distribution with 71 degrees of freedom.

d. t distribution with 70 degrees of freedom.

ANSWER:

d

POINTS:

1


DIFFICULTY:

Easy

LEARNING OBJE BSST.ASWC.17.10.02 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Unknown

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CH 10 - Inference About Means and Proportions with Two Populations

NATIONAL STAN United States - BUSPROG: Analytic
DARDS:

STATE STANDARD United States - AK - DISC: Hypothesis Testing
S:

KEYWORDS:

Bloom's: Apply

7. Two independent simple random samples are taken to test the difference between the means of two populations whose
standard deviations are not known, but are assumed to be equal. The sample sizes are n1 = 25 and n2 = 35. The correct
distribution to use is the


a. t distribution with 61 degrees of freedom.

b. t distribution with 60 degrees of freedom.

c. t distribution with 59 degrees of freedom.

d. t distribution with 58 degrees of freedom.

ANSWER:

d

POINTS:

1

DIFFICULTY:

Easy

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CH 10 - Inference About Means and Proportions with Two Populations

LEARNING OBJE BSST.ASWC.17.10.02 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Unknown


NATIONAL STAN United States - BUSPROG: Analytic
DARDS:

STATE STANDARD United States - AK - DISC: Hypothesis Testing
S:

KEYWORDS:

Bloom's: Apply

8. If two independent large samples are taken from two populations, the sampling distribution of the difference between
the two sample means

a. can be approximated by any distribution.

b. will have a variance of one.

c. can be approximated by a normal distribution.

d. will have a mean of one.

ANSWER:

c

POINTS:

1


DIFFICULTY:

Easy

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CH 10 - Inference About Means and Proportions with Two Populations

LEARNING OBJE BSST.ASWC.17.10.01 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Known

NATIONAL STAND United States - BUSPROG: Analytic
ARDS:

STATE STANDARD United States - AK - DISC: Statistical Inference
S:

KEYWORDS:

Bloom's: Remember

9. The standard error of

-

is the


a. pooled estimator of

-

.

b. variance of the sampling distribution of

-

.

c. standard deviation of the sampling distribution of

d. margin of error of

ANSWER:

c

POINTS:

1

-

-

.


.

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CH 10 - Inference About Means and Proportions with Two Populations

DIFFICULTY:

Easy

LEARNING OBJE BSST.ASWC.17.10.01 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Known

NATIONAL STAND United States - BUSPROG: Analytic
ARDS:

STATE STANDARD United States - AK - DISC: Statistical Inference
S:

KEYWORDS:

Bloom's: Remember

10. The sampling distribution of


-

is approximated by a

a. normal distribution.

b. t distribution with n1 + n2 degrees of freedom.

c. t distribution with n1 + n2 - 1 degrees of freedom.

d.

-

distribution.

ANSWER:

a

POINTS:

1

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CH 10 - Inference About Means and Proportions with Two Populations


DIFFICULTY:

Easy

LEARNING OBJECTI BSST.ASWC.17.10.04 - Inferences About the Difference Between Two
VES:
Population Proportions

NATIONAL STANDA United States - BUSPROG: Analytic
RDS:

STATE STANDARDS: United States - AK - DISC: Statistical Inference

KEYWORDS:

Bloom's: Remember

11. Salary information regarding male and female employees of a large company is shown below.

Male

Female

Sample Size

64

36


Sample Mean Salary (in $1000)

44

41

128

72

Population Variance ( )

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CH 10 - Inference About Means and Proportions with Two Populations

The point estimate of the difference between the means of the two populations is

a. -28.

b. 3.

c. 4.

d. -4.

ANSWER:


b

POINTS:

1

DIFFICULTY:

Easy

LEARNING OBJE BSST.ASWC.17.10.01 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Known

NATIONAL STAND United States - BUSPROG: Analytic
ARDS:

STATE STANDARD United States - AK - DISC: Statistical Inference
S:

KEYWORDS:

Bloom's: Apply

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CH 10 - Inference About Means and Proportions with Two Populations

12. Salary information regarding male and female employees of a large company is shown below.

Male

Female

Sample Size

64

36

Sample Mean Salary (in $1000)

44

41

128

72

Population Variance ( )

The standard error of the difference between the two sample means is

a. 4.


b. 7.46.

c. 4.24.

d. 2.0.

ANSWER:

d

POINTS:

1

DIFFICULTY:

Easy

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CH 10 - Inference About Means and Proportions with Two Populations

LEARNING OBJE BSST.ASWC.17.10.01 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Known

NATIONAL STAND United States - BUSPROG: Analytic

ARDS:

STATE STANDARD United States - AK - DISC: Statistical Inference
S:

KEYWORDS:

Bloom's: Apply

13. Salary information regarding male and female employees of a large company is shown below.

Male

Female

Sample Size

64

36

Sample Mean Salary (in $1000)

44

41

128

72


Population Variance ( )

At 95% confidence, the margin of error is

a. 1.960.

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CH 10 - Inference About Means and Proportions with Two Populations

b. 1.645.

c. 3.920.

d. 2.000.

ANSWER:

c

POINTS:

1

DIFFICULTY:


Easy

LEARNING OBJE BSST.ASWC.17.10.01 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Known

NATIONAL STAND United States - BUSPROG: Analytic
ARDS:

STATE STANDARD United States - AK - DISC: Interval Estimation
S:

KEYWORDS:

Bloom's: Apply

14. Salary information regarding male and female employees of a large company is shown below.

Male

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Female

Page 15


CH 10 - Inference About Means and Proportions with Two Populations

Sample Size


64

36

Sample Mean Salary (in $1000)

44

41

128

72

Population Variance ( )

The 95% confidence interval for the difference between the means of the two populations is

a. 0 to 6.92.

b. -2 to 2.

c. -1.96 to
1.96.

d. -.92 to 6.92.

ANSWER:


d

POINTS:

1

DIFFICULTY:

Easy

LEARNING OBJE BSST.ASWC.17.10.01 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Known

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CH 10 - Inference About Means and Proportions with Two Populations

NATIONAL STAND United States - BUSPROG: Analytic
ARDS:

STATE STANDARD United States - AK - DISC: Interval Estimation
S:

KEYWORDS:

Bloom's: Apply


15. Salary information regarding male and female employees of a large company is shown below.

Male

Female

Sample Size

64

36

Sample Mean Salary (in $1000)

44

41

128

72

Population Variance ( )

If you are interested in testing whether or not the population average salary of males is significantly greater than that of
females, the test statistic is

a. 2.0.


b. 1.5.

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CH 10 - Inference About Means and Proportions with Two Populations

c. 1.96.

d. 1.645.

ANSWER:

b

POINTS:

1

DIFFICULTY:

Easy

LEARNING OBJE BSST.ASWC.17.10.01 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Known

NATIONAL STAND United States - BUSPROG: Analytic

ARDS:

STATE STANDARD United States - AK - DISC: Hypothesis Testing
S:

KEYWORDS:

Bloom's: Apply

16. Salary information regarding male and female employees of a large company is shown below.

Sample Size

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Male

Female

64

36

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CH 10 - Inference About Means and Proportions with Two Populations

Sample Mean Salary (in $1000)


Population Variance ( )

44

41

128

72

If you are interested in testing whether or not the population average salary of males is significantly greater than that of
females, the p-value is

a. .0668.

b. .0334.

c. .1336.

d. .9332.

ANSWER:

a

POINTS:

1

DIFFICULTY:


Easy

LEARNING OBJE BSST.ASWC.17.10.01 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Known

NATIONAL STAND United States - BUSPROG: Analytic
ARDS:

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Page 19


CH 10 - Inference About Means and Proportions with Two Populations

STATE STANDARD United States - AK - DISC: Hypothesis Testing
S:

KEYWORDS:

Bloom's: Apply

17. Salary information regarding male and female employees of a large company is shown below.

Male

Female


Sample Size

64

36

Sample Mean Salary (in $1000)

44

41

128

72

Population Variance ( )

If you are interested in testing whether or not the population average salary of males is significantly greater than that of
females, at α = .05, the conclusion is that the population

a. average salary of males is significantly greater than females.

b. average salary of males is significantly lower than females.

c. salaries of males and females are equal.

d. average salary of males is greater than females cannot be proved.
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CH 10 - Inference About Means and Proportions with Two Populations

ANSWER:

d

POINTS:

1

DIFFICULTY:

Easy

LEARNING OBJE BSST.ASWC.17.10.01 - Inferences About the Difference Between Two
CTIVES:
Population Means: σ1 and σ2 Known

NATIONAL STAND United States - BUSPROG: Analytic
ARDS:

STATE STANDARD United States - AK - DISC: Hypothesis Testing
S:

KEYWORDS:

Bloom's: Understand


18. The following information was obtained from matched samples taken from two populations.
The daily production rates for a sample of workers before and after a training program are shown below. Assume the
population of differences is normally distributed.

Worker

Before

After

1

20

22

2

25

23

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CH 10 - Inference About Means and Proportions with Two Populations


3

27

27

4

23

20

5

22

25

6

20

19

7

17

18


The point estimate for the difference between the means of the two populations is

a. 1.

b. 2.

c. 0.

d. 1.

ANSWER:

c

POINTS:

1

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CH 10 - Inference About Means and Proportions with Two Populations

DIFFICULTY:

Easy

LEARNING OBJE BSST.ASWC.17.10.03 - Inferences About the Difference Between Two

CTIVES:
Population Means: Matched Samples

NATIONAL STAND United States - BUSPROG: Analytic
ARDS:

STATE STANDARD United States - AK - DISC: Statistical Inference
S:

KEYWORDS:

Bloom's: Apply

19. The following information was obtained from matched samples taken from two populations.
The daily production rates for a sample of workers before and after a training program are shown below. Assume the
population of differences is normally distributed.

Worker

Before

After

1

20

22

2


25

23

3

27

27

4

23

20

5

22

25

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CH 10 - Inference About Means and Proportions with Two Populations


6

20

19

7

17

18

The null hypothesis to be tested is H0: μd = 0. The test statistic is

a. -1.96.

b. 1.77.

c. 0.

d. 1.00.

ANSWER:

c

POINTS:

1


DIFFICULTY:

Moderate

LEARNING OBJE BSST.ASWC.17.10.03 - Inferences About the Difference Between Two
CTIVES:
Population Means: Matched Samples

NATIONAL STAND United States - BUSPROG: Analytic
ARDS:

STATE STANDARD United States - AK - DISC: Hypothesis Testing
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Page 24


CH 10 - Inference About Means and Proportions with Two Populations

S:

KEYWORDS:

Bloom's: Apply

20. The following information was obtained from matched samples taken from two populations.
The daily production rates for a sample of workers before and after a training program are shown below. Assume the
population of differences is normally distributed.

Worker


Before

After

1

20

22

2

25

23

3

27

27

4

23

20

5


22

25

6

20

19

7

17

18

Given that the null hypothesis to be tested is H0: μd = 0,

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Page 25