Chapter 8: Estimating the Mean of a Population

Test Bank

Multiple Choice

1. What is the term for a single value used to estimate an unknown population parameter?

a. point estimate

b. confidence interval

c. confidence limits

d. interval estimate

Cognitive Domain: Knowledge

Answer Location: Introduction to the Confidence Interval for the Mean

Difficulty Level: Easy

2. What is the term for the lower and upper boundaries of a confidence interval?

a. point estimate

b. confidence interval

c. confidence limits

d. interval estimate

Cognitive Domain: Knowledge

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Easy

3. What is the term for a range or interval of values that has a stated probability of containing an unknown population parameter?

a. point estimate

b. confidence interval

c. confidence limits

d. interval estimate

Cognitive Domain: Knowledge

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Easy

4. A point estimate is ______.

a. a measure of variability

b. a single value used to estimate an unknown population parameter

c. the lower boundary of a confidence interval

d. a range or interval of values that has a stated probability of containing an unknown population parameter

Cognitive Domain: Knowledge

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Easy

5. Confidence limits are ______.

a. a measure of variability

b. single values used to estimate an unknown population parameter

c. the lower and upper boundaries of a confidence interval

d. a range or interval of values that has a stated probability of containing an unknown population parameter

Cognitive Domain: Knowledge

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Easy

6. The confidence interval for the mean is ______.

a. a range of values for a variable that has a stated probability of containing an unknown population mean

b. a single value used to estimate an unknown population parameter

c. the lower and upper boundaries of the confidence interval

d. a measure of variability

Cognitive Domain: Knowledge

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Easy

7. A confidence interval is ______.

a. a measure of central tendency

b. a single value used to estimate an unknown population parameter

c. the upper boundary of a confidence interval

d. a range or interval of values that has a stated probability of containing an unknown population parameter

Cognitive Domain: Knowledge

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Easy

8. Use the formula to calculate the 95% confidence interval for a sample of N = 12 with a mean = 6.00 and standard error of the mean = 1.15.

a. 95% CI = 6.00 ± 2.53

b. 95% CI = 6.00 ± 2.07

c. 95% CI = 6.00 ± 3.57

d. 95% CI = 6.00 ± 3.35

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

9. Use the formula to calculate the 95% confidence interval for a sample of N = 22 with a mean = 9.51 and standard error of the mean = 1.25.

a. 95% CI = 9.51 ± 2.15

b. 95% CI = 9.51 ± 3.52

c. 95% CI = 9.51 ± 2.59

d. 95% CI = 9.51 ± 2.60

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

10. Calculate the 95% confidence interval for a sample of N = 15 with a mean = 3.50 and standard error of the mean = .21.

a. 95% CI = 3.50 ± .45

b. 95% CI = 3.50 ± .37

c. 95% CI = 3.50 ± .63

d. 95% CI = 3.50 ± 2.36

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

11. Calculate the 95% confidence interval for a sample of N = 21 with a mean = 73.51 and standard error of the mean = 2.97.

a. 95% CI = 73.51 ± 6.20

b. 95% CI = 73.51 ± 5.12

c. 95% CI = 73.51 ± 8.45

d. 95% CI = 73.51 ± 5.06

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

12. Calculate the 95% confidence interval for a sample of N = 24 with a mean = 102.97 and standard error of the mean = 1.85.

a. 95% CI = 102.97 ± 3.83

b. 95% CI = 102.97 ± 3.17

c. 95% CI = 102.97 ± 5.19

d. 95% CI = 102.97 ± 3.92

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

13. Calculate the 95% confidence interval for a sample of N = 25 with a mean = 4.06 and standard error of the mean = .27.

a. 95% CI = 4.06 ± .56

b. 95% CI = 4.06 ± .46

c. 95% CI = 4.06 ± .76

d. 95% CI = 4.06 ± 2.33

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

14. Calculate the 95% confidence interval for a sample of N = 15 with a mean = 3.50 and standard deviation (s) = .80.

a. 95% CI = 3.50 ± .45

b. 95% CI = 3.50 ± .37

c. 95% CI = 3.50 ± .63

d. 95% CI = 3.50 ± 2.36

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

15. Calculate the 95% confidence interval for a sample of N = 21 with a mean = 73.51 and standard deviation (s) = 13.62.

a. 95% CI = 73.51 ± 6.20

b. 95% CI = 73.51 ± 5.12

c. 95% CI = 73.51 ± 8.45

d. 95% CI = 73.51 ± 5.06

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

16. Calculate the 95% confidence interval for a sample of N = 24 with a mean = 102.97 and standard deviation (s) = 9.05.

a. 95% CI = 102.97 ± 3.83

b. 95% CI = 102.97 ± 3.17

c. 95% CI = 102.97 ± 5.19

d. 95% CI = 102.97 ± 3.92

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

17. Calculate the 95% confidence interval for a sample of N = 25 with a mean = 4.06 and standard deviation (s) = 1.37.

a. 95% CI = 4.06 ± .56

b. 95% CI = 4.06 ± .46

c. 95% CI = 4.06 ± .76

d. 95% CI = 4.06 ± 2.33

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

18. Calculate the 95% confidence interval for a sample of N = 29 with a mean = 52.49 and standard deviation (s) = 11.58.

a. 95% CI = 52.49 ± 4.40

b. 95% CI = 52.49 ± 3.66

c. 95% CI = 52.49 ± 5.94

d. 95% CI = 52.49 ± 4.20

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

19. Calculate the 95% confidence interval for a sample of N = 30 with a mean = 7.12 and standard deviation (s) = 3.67.

a. 95% CI = 7.12 ± 1.37

b. 95% CI = 7.12 ± 1.14

c. 95% CI = 7.12 ± 1.84

d. 95% CI = 7.12 ± 2.72

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

20. Use the formula to calculate the lower and upper limits of the 95% confidence interval for a sample of N = 12 with a mean = 6.00 and standard error of the mean = 1.15.

a. (3.47, 8.53)

b. (3.93, 8.07)

c. (2.43, 9.57)

d. (2.65, 9.35)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

21. Calculate the lower and upper limits of the 95% confidence interval for a sample of N = 25 with a mean = 10.50 and standard deviation (s) = 4.16.

a. (8.83, 12.17)

b. (8.78, 12.22)

c. (8.17, 12.83)

d. (7.59, 13.41)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

22. Calculate the lower and upper limits of the 95% confidence interval for a sample of N = 29 with a mean = 52.49 and standard error of the mean = 2.15.

a. (48.29, 56.69)

b. (48.83, 56.15)

c. (46.55, 58.43)

d. (48.09, 56.89)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

23. Calculate the lower and upper limits of the 95% confidence interval for a sample of N = 24 with a mean = 102.97 and standard error of the mean = 1.85.

a. (99.14, 106.80)

b. (99.8, 106.14)

c. (97.78, 108.16)

d. (99.05, 106.89)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

24. Calculate the lower and upper limits of the 95% confidence interval for a sample of N = 25 with a mean = 4.06 and standard error of the mean = .27.

a. (3.50, 4.62)

b. (3.60, 4.52)

c. (3.30, 4.82)

d. (1.73, 6.39)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

25. Calculate the lower and upper limits of the 95% confidence interval for a sample of N = 28 with a mean = 16.39 and standard error of the mean = .91.

a. (14.52, 18.26)

b. (14.84, 17.94)

c. (13.87, 18.91)

d. (13.43, 19.35)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

26. Which of the following statements would be the correct way to state a conclusion regarding a 95% confidence interval?

a. There is a .05 probability that the population mean is between 35,422 and 41,566.

b. There is a .95 probability that the interval of 35,422 to 41,566 contains the population mean.

c. There is a .95 probability that the population mean is between 35,422 and 41,566.

d. There is a .05 probability that the interval of 35,422 to 41,566 contains the population mean.

Cognitive Domain: Application

Answer Location: Draw a Conclusion About The Confidence Interval

Difficulty Level: Hard

27. Which of the following statements would be the correct way to state a conclusion regarding a 95% confidence interval?

a. There is a 95% probability that the population mean is between 131.65 and 135.78.

b. There is a .95 probability that the population mean is between 131.65 and 135.78.

c. There is a .95 probability that the interval of 131.65 and 135.78 contains the population mean.

d. There is a 95% probability that the interval of 131.65 and 135.78 contains the population mean.

Cognitive Domain: Application

Answer Location: Draw A Conclusion About the Confidence Interval

Difficulty Level: Hard

28. Use the formula to calculate the 95% confidence interval for a sample with a mean = 7.00 and a population standard error of the mean = .50.

a. 95% CI = 7.00 ± .98

b. 95% CI = 7.00 ± .83

c. 95% CI = 7.00 ± 1.29

d. 95% CI = 7.00 ± 2.46

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

29. Calculate the 95% confidence interval for a sample with a mean = 12.67 and a population standard error of the mean = .98.

a. 95% CI = 12.67 ± 1.61

b. 95% CI = 12.67 ± 1.92

c. 95% CI = 12.67 ± 2.28

d. 95% CI = 12.67 ± 2.52

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

30. Calculate the 95% confidence interval for a sample with a mean = 2.50 and a population standard error of the mean = .20.

a. 95% CI = 2.50 ± .39

b. 95% CI = 2.50 ± .33

c. 95% CI = 2.50 ± .52

d. 95% CI = 2.50 ± 2.16

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

31. Calculate the 95% confidence interval for a sample with a mean = 57.28 and a population standard error of the mean = 3.27.

a. 95% CI = 57.28 ± 6.41

b. 95% CI = 57.28 ± 5.40

c. 95% CI = 57.28 ± 8.44

d. 95% CI = 57.28 ± 5.23

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

32. Calculate the 95% confidence interval for a sample with a mean = 15.86 and a population standard error of the mean = 1.89.

a. 95% CI = 15.86 ± 3.70

b. 95% CI = 15.86 ± 3.12

c. 95% CI = 15.86 ± 4.88

d. 95% CI = 15.86 ± 3.85

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

33. Calculate the 95% confidence interval for a sample with a mean = 117.52 and a population standard error of the mean = 5.57.

a. 95% CI = 117.52 ± 10.92

b. 95% CI = 117.52 ± 9.19

c. 95% CI = 117.52 ± 14.37

d. 95% CI = 117.52 ± 7.53

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

34. Calculate the 95% confidence interval for a sample with a mean = 249.60 and a population standard error of the mean = 9.13.

a. 95% CI = 249.60 ± 17.89

b. 95% CI = 249.60 ± 15.06

c. 95% CI = 249.60 ± 23.56

d. 95% CI = 249.60 ± 11.09

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

35. Calculate the 95% confidence interval for a sample of N = 17 with a mean = 12.42 and a population standard deviation (σ) = 5.00.

a. 95% CI = 12.42 ± 2.37

b. 95% CI = 12.42 ± 2.00

c. 95% CI = 12.42 ± 3.12

d. 95% CI = 12.42 ± 3.17

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

36. Calculate the 95% confidence interval for a sample of N = 25 with a mean = 3.74 and a population standard deviation (σ) = 6.00.

a. 95% CI = 3.74 ± 2.35

b. 95% CI = 3.74 ± 1.98

c. 95% CI = 3.74 ± 3.10

d. 95% CI = 3.74 ± 3.16

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

37. Calculate the 95% confidence interval for a sample of N = 28 with a mean = 15.86 and a population standard deviation (σ) = 10.00.

a. 95% CI = 15.86 ± 3.12

b. 95% CI = 15.86 ± 3.70

c. 95% CI = 15.86 ± 4.88

d. 95% CI = 15.86 ± 3.85

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

38. Calculate the 95% confidence interval for a sample of N = 30 with a mean = 249.60 and a population standard deviation (σ) = 50.00.

a. 95% CI = 249.60 ± 23.56

b. 95% CI = 249.60 ± 15.06

c. 95% CI = 249.60 ± 17.89

d. 95% CI = 249.60 ± 11.09

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

39. Calculate the lower and upper limits of the 95% confidence interval for a sample with a mean = 7.00 and a population standard error of the mean = .50.

a. (6.02, 7.98)

b. (6.18, 7.83)

c. (5.71, 8.29)

d. (4.54, 9.46)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

40. Calculate the lower and upper limits of the 95% confidence interval for a sample with a mean = 2.50 and a population standard error of the mean = .20.

a. (2.11, 2.89)

b. (2.17, 2.83)

c. (1.98, 3.02)

d. (.34, 4.66)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

41. Calculate the lower and upper limits of the 95% confidence interval for a sample with a mean = 28.59 and a population standard error of the mean = 2.29.

a. (24.10, 33.08)

b. (24.81, 32.37)

c. (22.68, 34.50)

d. (24.34, 32.84)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

42. Calculate the lower and upper limits of the 95% confidence interval for a sample with a mean = 57.28 and a population standard error of the mean = 3.27.

a. (40.87, 63.69)

b. (51.88, 62.68)

c. (48.84, 65.72)

d. (52.05, 62.51)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

43. Calculate the lower and upper limits of the 95% confidence interval for a sample with a mean = 12.67 and a population standard error of the mean = .98.

a. (11.06, 14.28)

b. (10.75, 14.59)

c. (10.39, 14.95)

d. (10.15, 15.19)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

44. There is a .95 probability that a confidence interval contains the ______ score for the population.

a. median

b. mean

c. standard deviation

d. variance

Cognitive Domain: Comprehension

Answer Location: Draw a Conclusion About the Confidence Interval

Difficulty Level: Medium

45. When drawing a conclusion about the 95% confidence interval with a known population standard deviation, a researcher would state that there is a ______.

a. .95 probability that a confidence interval contains the median score for the population

b. 95% probability that a confidence interval contains the mean score for the population

c. .95 probability that a confidence interval contains the mean score for the population

d. .05 probability that a confidence interval contains the mean score for the population

Cognitive Domain: Comprehension

Answer Location: Draw a Conclusion About the Confidence Interval

Difficulty Level: Medium

46. What is the relationship between the size of a sample and the width of the confidence interval for the mean?

a. The smaller the sample size, the narrower the confidence interval for the mean.

b. The larger the sample size, the narrower the confidence interval for the mean.

c. The larger the sample size, the wider the confidence interval for the mean.

d. The size of the sample has no influence on the width of the confidence interval for the mean.

Cognitive Domain: Knowledge

Answer Location: Sample Size

Difficulty Level: Easy

47. The larger the sample size, the ______ the confidence interval for the mean.

a. narrower

b. wider

c. broader

d. more significant

Cognitive Domain: Knowledge

Answer Location: Sample Size

Difficulty Level: Easy

48. When a sample size is increased, the confidence interval for the mean is then ______.

a. more significant

b. widened

c. narrowed

d. less significant

Cognitive Domain: Knowledge

Answer Location: Sample Size

Difficulty Level: Easy

49. When a sample size is decreased, the confidence interval for the mean is then ______.

a. narrowed

b. widened

c. more significant

d. less significant

Cognitive Domain: Knowledge

Answer Location: Sample Size

Difficulty Level: Easy

50. If a researcher were to increase the sample size from 100 to 200, the confidence interval for the mean would be ______.

a. widened

b. narrowed

c. unchanged

d. more normally distributed

Cognitive Domain: Comprehension

Answer Location: Sample Size

Difficulty Level: Medium

51. A sample size of ______ would have the widest confidence interval for the mean.

a. N = 200

b. N = 250

c. N = 300

d. N = 350

Cognitive Domain: Comprehension

Answer Location: Sample Size

Difficulty Level: Medium

52. A sample of size ______ would have the narrowest confidence interval for the mean.

a. N = 140

b. N = 200

c. N = 300

d. N = 425

Cognitive Domain: Comprehension

Answer Location: Sample Size

Difficulty Level: Medium

53. The relationship between sample size and the width of a confidence interval may be explained by the concept of ______.

a. z score

b. point estimates

c. sampling error

d. descriptive statistics

Cognitive Domain: Knowledge

Answer Location: Sample Size

Difficulty Level: Easy

54. The distribution of sample means for larger samples is more closely clustered around the population mean, with less ______ among sample means.

a. confidence

b. significance

c. similarity

d. variability

Cognitive Domain: Knowledge

Answer Location: Sample Size

Difficulty Level: Easy

55. The distribution of sample means for relatively ______ samples is closely clustered around the population mean, with less variability among sample means.

a. large

b. small

c. normally distributed

d. skewed

Cognitive Domain: Knowledge

Answer Location: Sample Size

Difficulty Level: Easy

56. The ______ the sample, the more confidence a researcher has that the sample mean estimates the unknown population mean μ, and the ______ the confidence interval around the sample mean.

a. larger; larger

b. smaller; smaller

c. smaller; larger

d. larger; smaller

Cognitive Domain: Comprehension

Answer Location: Sample Size

Difficulty Level: Medium

57. The ______ the sample, the less confidence a research has that the sample mean estimates the unknown population mean μ, and the ______ the confidence interval around the sample mean.

a. larger; smaller

b. larger; larger

c. smaller; larger

d. smaller; smaller

Cognitive Domain: Comprehension

Answer Location: Sample Size

Difficulty Level: Medium

58. Researchers have more confidence that the sample mean estimates the unknown population mean when their sample is ______.

a. centralized

b. significant

c. larger

d. smaller

Cognitive Domain: Comprehension

Answer Location: Sample Size

Difficulty Level: Medium

59. ______ samples have ______ value for the standard error of the mean, which in turn narrows the width of the confidence interval.

a. Larger; larger

b. Smaller; smaller

c. Larger; smaller

d. Smaller; larger

Cognitive Domain: Comprehension

Answer Location: Sample Size

Difficulty Level: Medium

60. The ______ the desired width of a confidence interval, the ______ the necessary sample size.

a. larger; larger

b. smaller; smaller

c. larger; smaller

d. smaller; larger

Cognitive Domain: Comprehension

Answer Location: Estimating the Sample Size Needed for a Desired Confidence Interval

Difficulty Level: Medium

61. For a variable with = 15.00, how large should the sample be for a desired 95% confidence interval width of 6?

a. 10

b. 24

c. 96

d. 576

Cognitive Domain: Application

Answer Location: Estimating the Sample Size Needed for a Desired Confidence Interval

Difficulty Level: Hard

62. For a variable with = 25.00, how large should the sample be for a desired 95% confidence interval width of 15?

a. 7

b. 11

c. 43

d. 121

Cognitive Domain: Application

Answer Location: Estimating the Sample Size Needed for a Desired Confidence Interval

Difficulty Level: Hard

63. For a variable with = 3.50, how large should the sample be for a desired 95% confidence interval width of 1.50?

a. 9

b. 21

c. 84

d. 441

Cognitive Domain: Application

Answer Location: Estimating the Sample Size Needed for a Desired Confidence Interval

Difficulty Level: Hard

64. For a variable with = 175.00, how large should the sample be for a desired 95% confidence interval width of 50?

a. 14

b. 47

c. 188

d. 2209

Cognitive Domain: Application

Answer Location: Estimating the Sample Size Needed for a Desired Confidence Interval

Difficulty Level: Hard

65. For a variable with = 333.00, how large should the sample be for a desired 95% confidence interval width of 100?

a. 13

b. 43

c. 170

d. 1849

Cognitive Domain: Application

Answer Location: Estimating the Sample Size Needed for a Desired Confidence Interval

Difficulty Level: Hard

66. For a variable with = 5.81, how large should the sample be for a desired 95% confidence interval width of 2?

a. 11

b. 32

c. 130

d. 1024

Cognitive Domain: Application

Answer Location: Estimating the Sample Size Needed for a Desired Confidence Interval

Difficulty Level: Hard

67. The ______ the desired width of a confidence interval, the ______ the necessary sample size.

a. larger; larger

b. smaller; smaller

c. larger; smaller

d. smaller; larger

Cognitive Domain: Knowledge

Answer Location: Estimating the Sample Size Needed for a Desired Confidence Interval

Difficulty Level: Easy

68. Which of the following affects the width of a confidence interval?

a. whether the population standard deviation is known

b. the sample mean

c. the desired level of confidence

d. the population mean

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

69. The ______ the desired level of confidence, the ______ the confidence interval for the mean.

a. higher; wider

b. lower; narrower

c. higher; narrower

d. lower; wider

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

70. The ______ the desired level of confidence, the ______ the confidence interval for the mean.

a. higher; narrower

b. lower; narrower

c. lower; wider

d. lower; higher

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

71. When a researcher moves from a 90% confidence level to a 95% confidence level, the width of the confidence interval for the mean is ______.

a. increased

b. unchanged

c. less significant

d. decreased

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

72. When a researcher moves from a 95% confidence level to a 99% confidence level, the confidence interval for the mean becomes ______.

a. wider

b. normally distributed

c. statistically significant

d. narrower

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

73. When a researcher moves from a 95% confidence level to a 90% confidence level, the confidence interval for the mean becomes ______.

a. wider

b. normally distributed

c. statistically significant

d. narrower

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

74. If a researcher decreases the confidence level from 99% to 90%, the confidence interval for the mean is ______.

a. widened

b. unchanged

c. narrowed

d. restricted

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

75. When a researcher increases the confidence level from 95% to 99%, the wider interval implies ______.

a. increased precision in estimating the population mean

b. a lower confidence that the interval contains the population mean

c. a loss of precision in estimating the sample mean

d. decreased precision in estimating the population mean

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

76. If a researcher chooses a confidence level less than the 95%, which of the following occurs?

a. a smaller confidence interval that contains the population mean

b. a larger confidence interval that contain the population mean

c. a loss of precision in estimating the sample mean

d. a loss of precision in estimating the population mean

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

77. If a researcher chooses a confidence level greater than the 95%, which of the following will occur?

a. a smaller confidence interval that contains the population mean

b. a larger confidence interval that contain the population mean

c. a loss of precision in estimating the sample mean

d. a loss of precision in estimating the population mean

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

78. Which confidence interval is the narrowest?

a. 99.9%

b. 99%

c. 95%

d. 90%

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

79. Which confidence interval is the widest?

a. 99.9%

b. 99%

c. 95%

d. 90%

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

80. Use the formula to calculate the 90% confidence interval for a sample of N = 12 with a mean = 4.00 and standard error of the mean = .58.

a. 90% CI = 4.00 ± 1.04

b. 90% CI = 4.00 ± 1.80

c. 90% CI = 4.00 ± 2.38

d. 90% CI = 4.00 ± 1.28

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

81. Calculate the 90% confidence interval for a sample of N = 17 with a mean = 18.43 and standard error of the mean = .72.

a. 90% CI = 18.43 ± 1.26

b. 90% CI = 18.43 ± 2.10

c. 90% CI = 18.43 ± 2.47

d. 90% CI = 18.43 ± 1.53

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

82. Calculate the 90% confidence interval for a sample of N = 21 with a mean = 65.25 and standard error of the mean = 2.57.

a. 90% CI = 65.25 ± 4.43

b. 90% CI = 65.25 ± 7.31

c. 90% CI = 65.25 ± 4.30

d. 90% CI = 65.25 ± 5.36

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

83. Calculate the 90% confidence interval for a sample of N = 25 with a mean = 2.75 and standard error of the mean = .19.

a. 90% CI = 2.75 ± .33

b. 90% CI = 2.75 ± .53

c. 90% CI = 2.75 ± 1.90

d. 90% CI = 2.75 ± .39

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Medium

84. Calculate the 90% confidence interval for a sample of N = 29 with a mean = 137.98 and standard error of the mean = 4.98.

a. 90% CI = 137.98 ± 8.47

b. 90% CI = 137.98 ± 13.76

c. 90% CI = 137.98 ± 6.68

d. 90% CI = 137.98 ± 10.20

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

85. Calculate the 90% confidence interval for a sample of N = 17 with a mean = 18.43 and standard deviation (s) = 2.96.

a. 90% CI = 18.43 ± 1.26

b. 90% CI = 18.43 ± 2.10

c. 90% CI = 18.43 ± 2.47

d. 90% CI = 18.43 ± 1.53

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

86. Calculate the 90% confidence interval for a sample of N = 25 with a mean = 2.75 and standard deviation (s) = .93.

a. 90% CI = 2.75 ± .33

b. 90% CI = 2.75 ± .53

c. 90% CI = 2.75 ± 1.90

d. 90% CI = 2.75 ± .39

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

87. Calculate the 90% confidence interval for a sample of N = 29 with a mean = 137.98 and standard deviation (s) = 26.84.

a. 90% CI = 137.98 ± 8.47

b. 90% CI = 137.98 ± 13.76

c. 90% CI = 137.98 ± 6.68

d. 90% CI = 137.98 ± 10.20

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

88. Use the formula to calculate the lower and upper limits of the 90% confidence interval for a sample of N = 12 with a mean = 4.00 and standard error of the mean = .58.

a. (2.96, 5.04)

b. (2.20, 5.80)

c. 1.62, 6.38)

d. 2.72, 5.28)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

89. Calculate the lower and upper limits of the 90% confidence interval for a sample of N = 17 with a mean = 18.43 and standard error of the mean = .72.

a. (17.17, 19.69)

b. (16.33, 20.53)

c. (15.96, 20.90)

d. 16.90, 19.96)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

90. Calculate the lower and upper limits of the 90% confidence interval for a sample of N = 29 with a mean = 137.98 and standard error of the mean = 4.98.

a. (129.51, 146.45)

b. (124.22, 151.74)

c. (131.30, 144.66)

d. (127.78, 148.18)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

91. Use the formula to calculate the 99% confidence interval for a sample of N = 15 with a mean = 7.50 and standard error of the mean = .32.

a. 99% CI = 7.50 ± .69

b. 99% CI = 7.50 ± .56

c. 99% CI = 7.50 ± .95

d. 99% CI = 7.50 ± 3.30

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

92. Calculate the 99% confidence interval for a sample of N = 19 with a mean = 27.18 and standard error of the mean = 2.37.

a. 99% CI = 27.18 ± 4.98

b. 99% CI = 27.18 ± 4.11

c. 99% CI = 27.18 ± 6.82

d. 99% CI = 27.18 ± 5.25

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

93. Calculate the 99% confidence interval for a sample of N = 24 with a mean = 96.55 and standard error of the mean = 1.54.

a. 99% CI = 96.55 ± 3.19

b. 99% CI = 96.55 ± 2.64

c. 99% CI = 96.55 ± 4.32

d. 99% CI = 96.55 ± 4.55

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

94. Calculate the 99% confidence interval for a sample of N = 28 with a mean = 13.64 and standard error of the mean = 1.04.

a. 99% CI = 13.64 ± 2.13

b. 99% CI = 13.64 ± 1.77

c. 99% CI = 13.64 ± 2.88

d. 99% CI = 13.64 ± 3.81

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

95. Calculate the 99% confidence interval for a sample of N = 30 with a mean = 1376.41 and standard error of the mean = 30.73.

a. 99% CI = 1376.41 ± 62.84

b. 99% CI = 1376.41 ± 52.15

c. 99% CI = 1376.41 ± 84.81

d. 99% CI = 1376.41 ± 33.48

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

96. Use the formula , where = to calculate the 99% confidence interval for a sample of N = 15 with a mean = 7.50 and standard deviation (s) = 1.25.

a. 99% CI = 7.50 ± .69

b. 99% CI = 7.50 ± .56

c. 99% CI = 7.50 ± .95

d. 99% CI = 7.50 ± 3.30

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

97. Calculate the 99% confidence interval for a sample of N = 19 with a mean = 27.18 and standard deviation (s) = 10.31.

a. 99% CI = 27.18 ± 4.98

b. 99% CI = 27.18 ± 4.11

c. 99% CI = 27.18 ± 6.82

d. 99% CI = 27.18 ± 5.25

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

98. Calculate the 99% confidence interval for a sample of N = 24 with a mean = 96.55 and standard deviation (s) = 7.54.

a. 99% CI = 96.55 ± 3.19

b. 99% CI = 96.55 ± 2.64

c. 99% CI = 96.55 ± 4.32

d. 99% CI = 96.55 ± 4.55

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

99. Calculate the 99% confidence interval for a sample of N = 28 with a mean = 13.64 and standard deviation (s) = 5.52.

a. 99% CI = 13.64 ± 2.13

b. 99% CI = 13.64 ± 1.77

c. 99% CI = 13.64 ± 2.88

d. 99% CI = 13.64 ± 3.81

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

100. Use the formula to calculate the lower and upper limits of the 99% confidence interval for a sample of N = 15 with a mean = 7.50 and standard error of the mean = .32.

a. (6.81, 8.19)

b. (6.94, 8.06)

c. (6.55, 8.45)

d. (4.20, 10.80)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

101. Calculate the lower and upper limits of the 99% confidence interval for a sample of N = 24 with a mean = 96.55 and standard error of the mean = 1.54.

a. (93.36, 99.74)

b. (93.91, 99.19)

c. (92.23, 100.87)

d. (90.20, 102.90)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

102. Calculate the lower and upper limits of the 99% confidence interval for a sample of N = 28 with a mean = 13.64 and standard error of the mean = 1.04.

a. (11.51, 15.77)

b. (11.87, 15.4)

c. (10.76, 16.52)

d. (9.83, 17.45)

Cognitive Domain: Application

Answer Location: Calculate the Confidence Interval and Confidence Limits

Difficulty Level: Hard

103. If a researcher wants a wider confidence interval, which of the following would be calculated?

a. 99% confidence interval

b. 95% confidence interval

c. 90% confidence interval

d. 85% confidence interval

Cognitive Domain: Knowledge

Answer Location: Choosing Between Different Levels of Confidence: Probability Versus Precision

Difficulty Level: Easy

104. If a researcher wants a narrower confidence interval, which of the following would be calculated?

a. 99% confidence interval

b. 95% confidence interval

c. 90% confidence interval

d. 85% confidence interval

Cognitive Domain: Knowledge

Answer Location: Choosing Between Different Levels of Confidence: Probability Versus Precision

Difficulty Level: Easy

105. If a researcher wants a more precise confidence interval, which of the following would be calculated?

a. 99.9% confidence interval

b. 99% confidence interval

c. 95% confidence interval

d. 90% confidence interval

Cognitive Domain: Knowledge

Answer Location: Choosing Between Different Levels of Confidence: Probability Versus Precision

Difficulty Level: Easy

106. Which of the following confidence intervals has the least precision?

a. 99% confidence interval

b. 95% confidence interval

c. 90% confidence interval

d. 85% confidence interval

Cognitive Domain: Knowledge

Answer Location: Choosing Between Different Levels of Confidence: Probability Versus Precision

Difficulty Level: Easy

107. Which of the following confidence intervals has the most precision?

a. 99% confidence interval

b. 95% confidence interval

c. 90% confidence interval

d. 85% confidence interval

Cognitive Domain: Knowledge

Answer Location: Choosing Between Different Levels of Confidence: Probability Versus Precision

Difficulty Level: Easy

108. As the sample size increases, which of the following is TRUE about the level of confidence?

a. The level of confidence has more of an impact on the width of the confidence interval.

b. The level of confidence has less of an impact on the width of the confidence interval.

c. The level of confidence has no impact on the width of the confidence interval.

d. The level of confidence does not change the width of the confidence interval.

Cognitive Domain: Comprehension

Answer Location: Choosing Between Different Levels of Confidence: Probability Versus Precision

Difficulty Level: Medium

109. As the sample size decreases, which of the following is TRUE about the level of confidence?

a. The level of confidence has more of an impact on the width of the confidence interval.

b. The level of confidence has less of an impact on the width of the confidence interval.

c. The level of confidence has no impact on the width of the confidence interval.

d. The level of confidence does not change the width of the confidence interval.

Cognitive Domain: Comprehension

Answer Location: Choosing Between Different Levels of Confidence: Probability Versus Precision

Difficulty Level: Medium

110. When a researcher chooses the 90% confidence level instead of the 95% confidence level, which of the following would be true for their decision?

a. The width of the confidence interval would be less precise.

b. The width of the confidence interval would be the same.

c. The width of the confidence interval would be larger.

d. The width of the confidence interval would be smaller.

Cognitive Domain: Comprehension

Answer Location: Choosing Between Different Levels of Confidence: Probability Versus Precision

Difficulty Level: Medium

111. Assuming the sample mean and standard deviation are the same for different combinations of levels of confidence and sample size, as the sample size ______, the level of confidence has ______ impact on the width of the confidence interval.

a. decreases; the same

b. decreases; less

c. increases; more

d. increases; less

Cognitive Domain: Comprehension

Answer Location: Choosing Between Different Levels of Confidence: Probability versus precision

Difficulty Level: Medium

112. For larger sample sizes, the level of confidence has less of an impact on the width of the confidence interval than for smaller sample sizes. This would indicate that there is a trade-off between ______.

a. probability and precision

b. confidence levels and confidence intervals

c. sample sizes

d. upper and lower limits

Cognitive Domain: Comprehension

Answer Location: Choosing Between Different Levels of Confidence: Probability Versus Precision

Difficulty Level: Medium

113. If a researcher chooses the 99% confidence interval instead of the 95% confidence interval, how does it affect the critical value of t?

a. Critical value of t is lower.

b. Critical value of t is higher.

c. Critical value of t is unchanged.

d. Critical value of t is not dependent on the confidence interval chosen.

Cognitive Domain: Comprehension

Answer Location: Choosing Between Different Levels of Confidence: Probability Versus Precision

Difficulty Level: Medium

114. Researchers have suggested that hypothesis testing be replaced with or supplemented by ______.

a. interval estimation

b. descriptive statistics

c. qualitative research

d. bivariate analysis

Cognitive Domain: Knowledge

Answer Location: Interval Estimation as an Alternative to Hypothesis Testing

Difficulty Level: Easy

115. Which of the following is a reason to retain hypothesis testing?

a. In complex research situations, it may not be possible to do interval estimation.

b. Calculating confidence intervals is too complicated.

c. Researchers cannot agree as to what is the appropriate level of confidence.

d. In simple research situations, confidence intervals would not be reliable.

Cognitive Domain: Analysis

Answer Location: Interval Estimation as an Alternative to Hypothesis Testing

Difficulty Level: Medium

116. Confidence intervals, like inferential statistics such as the t-statistic, are affected by which of the following?

a. normal curve

b. sample size

c. effect size

d. point estimate

Cognitive Domain: Analysis

Answer Location: Interval Estimation as an Alternative to Hypothesis Testing

Difficulty Level: Medium

117. According to the author of the book, the flaws and weaknesses of hypothesis testing are NOT inherent to the statistical procedures themselves, but are rather a function of how researchers ______.

a. estimate sample and population parameters

b. gather their data during the data collection process

c. input their data

d. use and interpret these procedures

Cognitive Domain: Analysis

Answer Location: Interval Estimation as an Alternative to Hypothesis Testing

Difficulty Level: Medium

118. When the null hypothesis is NOT rejected, the results of the analysis may be described as ______.

a. “insignificant”

b. “nonsignificant”

c. “significant”

d. “highly significant”

Cognitive Domain: Knowledge

Answer Location: The Interpretation of Statistical Significance and Nonsignificant

Difficulty Level: Easy

119. When the null hypothesis is rejected, the results of the analysis may be described as ______.

a. “insignificant”

b. “nonsignificant”

c. “significant”

d. “highly significant”

Cognitive Domain: Knowledge

Answer Location: The Interpretation of Statistical Significance and Nonsignificant

Difficulty Level: Easy

120. The concerns about hypothesis testing are NOT inherent in hypothesis tests, but rather due to ______.

a. the sample size chosen by the researcher

b. how researchers interpret the results of statistical analyses

c. how researchers implement the tests

d. the confidence level chosen by the researcher

Cognitive Domain: Comprehension

Answer Location: Concerns About Hypothesis Testing

Difficulty Level: Medium

True/False

1. A confidence interval is defined as a range of values likely containing a known population parameter.

Cognitive Domain: Comprehension

Answer Location: Introduction to the Confidence Interval for the Mean

Difficulty Level: Medium

2. To be useful, a confidence interval must have a desired level of confidence less than 100%.

Cognitive Domain: Knowledge

Answer Location: State the Desired Level of Confidence

Difficulty Level: Easy

3. The larger the sample size, the wider the confidence interval for the mean.

Cognitive Domain: Comprehension

Answer Location: Sample Size

Difficulty Level: Medium

4. A confidence level of 99% has a higher probability of containing the population mean than does a 95% confidence interval.

Cognitive Domain: Knowledge

Answer Location: Level of Confidence

Difficulty Level: Easy

5. The higher the desired level of confidence, the larger the confidence interval.

Cognitive Domain: Comprehension

Answer Location: Choosing Between Different Levels of Confidence: Probability Versus Precision

Difficulty Level: Medium