Chapter 08 Interval Estimation PDF

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Chapter 08 - Interval Estimation Multiple Choice 1. In interval estimation, as the sample size becomes larger, the interval estimate a. becomes narrower. b. becomes wider. c. remains the same, because the mean is not changing. d. gets closer to 1.96. ANSWER: a POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known NATIONAL STANDARDS: United States - BUSPROG: Analytic STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Remember DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 2. In an interval estimation for a proportion of a population, the value of z at 99.2% confidence is a. 2.65. b. 2.41. c. 1.96. d. 1.645. ANSWER: a POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.04 - Population Proportion NATIONAL STANDARDS: United States - BUSPROG: Analytic STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Apply DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 3. When s is used to estimate σ, the margin of error is computed by using the a. normal distribution. b. t distribution. c. mean of the sample. d. mean of the population. ANSWER: b Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation POINTS: DIFFICULTY: QUESTION TYPE: HAS VARIABLES: LEARNING OBJECTIVES: NATIONAL STANDARDS: STATE STANDARDS: KEYWORDS: DATE CREATED: DATE MODIFIED:

1 Easy Multiple Choice False BSST.ASWC.20.08.02 - Population Mean: σ Unknown United States - BUSPROG: Reflective Thinking United States - AK - DISC: Interval Estimation Bloom's: Remember 9/26/2018 11:25 AM 1/28/2019 11:09 AM

4. From a population with a variance of 484, a sample of 256 items is selected. At 95% confidence, the margin of error is a. 16. b. 1.375. c. 2.695. d. 22. ANSWER: c POINTS: 1 DIFFICULTY: Moderate QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known NATIONAL STANDARDS: United States - BUSPROG: Analytic STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Apply DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 5. A population has a standard deviation of 25. A random sample of 125 items from this population is selected. The sample mean is determined to be 325. At 95% confidence, the margin of error is a. 2.24. b. 5. c. 4.38. d. 11.18. ANSWER: c POINTS: 1 DIFFICULTY: Moderate QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Apply DATE CREATED: 9/26/2018 11:25 AM Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation DATE MODIFIED:

1/28/2019 11:09 AM

6. In order to determine an interval for the mean of a population with unknown standard deviation, a sample of 58 items is selected. The mean of the sample is determined to be 36. The associated number of degrees of freedom for reading the t value is a. 35. b. 36. c. 57. d. 58. ANSWER: c POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.02 - Population Mean: σ Unknown NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Apply DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 7. If we want to provide a 95% confidence interval for the mean of a population, the confidence coefficient will be a. .485. b. 1.96. c. .95. d. 1.645. ANSWER: c POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known NATIONAL STANDARDS: United States - BUSPROG: Analytic STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Remember DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 8. As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution a. becomes larger. b. becomes smaller. c. stays the same. d. fluctuates. Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation ANSWER: POINTS: DIFFICULTY: QUESTION TYPE: HAS VARIABLES: LEARNING OBJECTIVES: NATIONAL STANDARDS: STATE STANDARDS: KEYWORDS: DATE CREATED: DATE MODIFIED:

b 1 Easy Multiple Choice False BSST.ASWC.20.08.02 - Population Mean: σ Unknown United States - BUSPROG: Reflective Thinking United States - AK - DISC: Interval Estimation Bloom's: Remember 9/26/2018 11:25 AM 1/28/2019 11:09 AM

9. For the interval estimation of μwhen σis known and the sample is large, the proper distribution to use is the a. normal distribution. b. t distribution with n degrees of freedom. c. t distribution with n + 1 degrees of freedom. d. t distribution with n - 1 degrees of freedom. ANSWER: a POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Understand DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 10. An estimate of a population parameter that provides an interval of values believed to contain the value of the parameter is known as the a. confidence level. b. interval estimate. c. margin of error. d. point estimate. ANSWER: b POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08. - BSST.ASWC.17.08. NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation STATE STANDARDS: KEYWORDS: DATE CREATED: DATE MODIFIED:

United States - AK - DISC: Interval Estimation Bloom's: Remember 9/26/2018 11:25 AM 1/28/2019 11:09 AM

11. The value added to and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the a. confidence level. b. margin of error. c. parameter estimate. d. planning value. ANSWER: b POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08. - BSST.ASWC.17.08. NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Remember DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 12. In interval estimation, the t distribution is applicable only when the a. population has a mean of less than 30. b. sample standard deviation is used to estimate the population standard deviation. c. variance of the population is known. d. mean of the population is unknown. ANSWER: b POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.02 - Population Mean: σ Unknown NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Understand DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 13. In developing an interval estimate, if the population standard deviation is unknown, a. it is impossible to develop the interval estimate. Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation b. the standard deviation is arrived at using the range. c. the sample standard deviation must be used. d. it is assumed that the population standard deviation is 1. ANSWER: c POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.02 - Population Mean: σ Unknown NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Understand DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 14. From a population that is not normally distributed and whose standard deviation is not known, a sample of 6 items is selected to develop an interval estimate for the mean of the population (μ). a. The normal distribution can be used. b. The t distribution with 5 degrees of freedom must be used. c. The t distribution with 6 degrees of freedom must be used. d. The sample size must be increased. ANSWER: d POINTS: 1 DIFFICULTY: Moderate QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.02 - Population Mean: σ Unknown NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Understand DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 15. A sample of 200 elements from a population with a known standard deviation is selected. For an interval estimation of μ, the proper distribution to use is the a. normal distribution. b. t distribution with 200 degrees of freedom. c. t distribution with 201 degrees of freedom. d. t distribution with 199 degrees of freedom. Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation ANSWER: POINTS: DIFFICULTY: QUESTION TYPE: HAS VARIABLES: LEARNING OBJECTIVES: NATIONAL STANDARDS: STATE STANDARDS: KEYWORDS: DATE CREATED: DATE MODIFIED:

a 1 Easy Multiple Choice False BSST.ASWC.20.08.01 - Population Mean: σ Known United States - BUSPROG: Analytic United States - AK - DISC: Interval Estimation Bloom's: Understand 9/26/2018 11:25 AM 1/28/2019 11:09 AM

16. From a population that is normally distributed, a sample of 25 elements is selected and the standard deviation of the sample is computed. For the interval estimation of μ, the proper distribution to use is the a. normal distribution. b. t distribution with 25 degrees of freedom. c. t distribution with 26 degrees of freedom. d. t distribution with 24 degrees of freedom. ANSWER: d POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.02 - Population Mean: σ Unknown NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Understand DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 17. The z value for a 97.8% confidence interval estimation is a. 2.02. b. 1.96. c. 2.00. d. 2.29. ANSWER: d POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation NATIONAL STANDARDS: STATE STANDARDS: KEYWORDS: DATE CREATED: DATE MODIFIED:

United States - BUSPROG: Analytic United States - AK - DISC: Interval Estimation Bloom's: Apply 9/26/2018 11:25 AM 1/28/2019 11:09 AM

18. The t value for a 95% confidence interval estimation with 96 degrees of freedom is a. 1.661. b. 1.985. c. 1.291. d. 1.986. ANSWER: b POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.02 - Population Mean: σ Unknown NATIONAL STANDARDS: United States - BUSPROG: Analytic STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Apply DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 19. As the sample size increases, the margin of error a. increases. b. decreases. c. stays the same. d. fluctuates depending on the mean. ANSWER: b POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Remember DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 20. A 95% confidence interval for a population mean is determined to be 100 to 120. For the same data, if the confidence coefficient is reduced to .90, the confidence interval for μ a. becomes narrower. Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation b. becomes wider. c. does not change. d. becomes 100.1 to 120.1. ANSWER: a POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Understand DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 21. Using an α= .04, a confidence interval for a population proportion is determined to be .65 to .75. For the same data, if αis decreased, the confidence interval for the population proportion a. becomes narrower. b. becomes wider. c. uses a zero margin of error. d. remains the same. ANSWER: b POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJEC BSST.ASWC.20.08.01 - Population Mean: σ Known BSST.ASWC.20.08.04 - Population Proportion TIVES: NATIONAL STAND United States - BUSPROG: Analytic ARDS: STATE STANDARDS United States - AK - DISC: Interval Estimation : KEYWORDS: Bloom's: Understand DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 22. The ability of an interval estimate to contain the value of the population parameter is described by the a. confidence level. b. degrees of freedom. c. precise value of the population mean μ. d. point estimate. ANSWER: a POINTS: 1 Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation DIFFICULTY: QUESTION TYPE: HAS VARIABLES: LEARNING OBJECTIVES: NATIONAL STANDARDS: STATE STANDARDS: KEYWORDS: DATE CREATED: DATE MODIFIED:

Easy Multiple Choice False BSST.ASWC.20.08.01 - Population Mean: σ Known United States - BUSPROG: Reflective Thinking United States - AK - DISC: Interval Estimation Bloom's: Understand 9/26/2018 11:25 AM 1/28/2019 11:09 AM

23. If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect the a. width of the confidence interval to increase. b. width of the confidence interval to decrease. c. width of the confidence interval to remain the same. d. sample size to increase. ANSWER: a POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Understand DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 24. In general, higher confidence levels provide a. wider confidence intervals. b. narrower confidence intervals. c. a smaller standard error. d. unbiased estimates. ANSWER: a POINTS: 1 DIFFICULTY: Easy QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Understand DATE CREATED: 9/26/2018 11:25 AM Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation DATE MODIFIED:

1/28/2019 11:09 AM

25. A sample of 225 elements from a population with a standard deviation of 75 is selected. The sample mean is 180. The 98% confidence interval for μis a. 105 to 225. b. 175 to 185. c. 165.6 to 194.4. d. 164.575 to 195.425. ANSWER: d POINTS: 1 DIFFICULTY: Moderate QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Apply DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 26. A random sample of 64 observations has a mean of 20, a median of 21, and a mode of 22. The population standard deviation is known to equal 4.8. The 95.44% confidence interval for the population mean is a. 15.2 to 24.8. b. 18.8 to 21.2. c. 18.986 to 21.014. d. 21.2 to 22.8. ANSWER: b POINTS: 1 DIFFICULTY: Moderate QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.01 - Population Mean: σ Known NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Apply DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 27. When the level of confidence decreases, the margin of error a. stays the same. b. becomes smaller. c. becomes larger. d. becomes smaller or larger, depending on the sample mean. Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation ANSWER: POINTS: DIFFICULTY: QUESTION TYPE: HAS VARIABLES: LEARNING OBJECTIVES: NATIONAL STANDARDS: STATE STANDARDS: KEYWORDS: DATE CREATED: DATE MODIFIED:

b 1 Easy Multiple Choice False BSST.ASWC.20.08.01 - Population Mean: σ Known United States - BUSPROG: Reflective Thinking United States - AK - DISC: Interval Estimation Bloom's: Understand 9/26/2018 11:25 AM 1/28/2019 11:09 AM

28. A random sample of 64 students at a university showed an average age of 25 years and a sample standard deviation of 2 years. The 95% confidence interval for the true average age of all students in the university is a. 24.6 to 25.4. b. 24.5 to 25.5. c. 23.0 to 27.0. d. 20.0 to 30.0. ANSWER: b POINTS: 1 DIFFICULTY: Moderate QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.02 - Population Mean: σ Unknown NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Apply DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 29. A random sample of 49 statistics examinations was taken. The average score, in the sample, was 84 with a variance of 12.25. The 95% confidence interval for the average examination score of the population of the examinations is a. 83.45 to 84.55. b. 80.07 to 87.93. c. 83.29 to 84.71. d. 80.5 to 87.5. ANSWER: c POINTS: 1 Copyright Cengage Learning. Powered by Cognero.

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Chapter 08 - Interval Estimation DIFFICULTY: QUESTION TYPE: HAS VARIABLES: LEARNING OBJECTIVES: NATIONAL STANDARDS: STATE STANDARDS: KEYWORDS: DATE CREATED: DATE MODIFIED:

Moderate Multiple Choice False BSST.ASWC.20.08.02 - Population Mean: σ Unknown United States - BUSPROG: Reflective Thinking United States - AK - DISC: Interval Estimation Bloom's: Apply 9/26/2018 11:25 AM 1/28/2019 11:09 AM

30. The sample size needed to provide a margin of error of 3 or less with a .95 probability when the population standard deviation equals 11 is a. 10. b. 11. c. 51. d. 52. ANSWER: d POINTS: 1 DIFFICULTY: Moderate QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.03 - Determining the Sample Size NATIONAL STANDARDS: United States - BUSPROG: Reflective Thinking STATE STANDARDS: United States - AK - DISC: Interval Estimation KEYWORDS: Bloom's: Apply DATE CREATED: 9/26/2018 11:25 AM DATE MODIFIED: 1/28/2019 11:09 AM 31. It is known that the population variance equals 529. With a .95 probability, the sample size that needs to be taken if the desired margin of error is 4 or less is a. 508. b. 127. c. 509. d. 128. ANSWER: d POINTS: 1 DIFFICULTY: Moderate QUESTION TYPE: Multiple Choice HAS VARIABLES: False LEARNING OBJECTIVES: BSST.ASWC.20.08.03 - Determining the Sample Size NATIONAL STANDARDS: United States - ...