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Unformatted text preview: MULTIPLE CHOICE-QUESTIONS In the following multiple-choice questions, circle the correct answer. 1. An interval estimate is used to estimate a. a population parameter b. the sampling distribution c. a sample statistic d. the shape of the population's distribution ANSWER: a 2. As the sample size increases, the margin of error a. increases b. decreases c. stays the same d. None of the other answers are correct. ANSWER: b 3. The confidence associated with an interval estimate is called the a. level of significance b. degree of association c. confidence level d. precision ANSWER: c 4. 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 d. None of the other answers are correct. ANSWER: a 5. If we want to provide a 85% confidence interval for the mean of a population, the confidence coefficient is a. 0.15 b. 0.85 c. 1.96 d. 1.645 ANSWER: b 6. For the interval estimation of when is assumed known, the proper distribution to use is the a . t distribution with n- 2 degrees of freedom b. t distribution with n- 1 degrees of freedom c . t distribution with n degrees of freedom d. standard normal distribution ANSWER: d BUS 271 Study Guide Chapter 8 7. A random sample of 144 observations has a mean of 30, a median of 31, and a mode of 32. The population standard deviation is known to equal 6.0. The 95.44% confidence interval for the population mean is a. 29.00 to 31.00 b. 27.44 to 32.56 c. 25.56 to 34.56 d. 26.56 to 35.56 ANSWER: a Exhibit A In order to estimate the average time spent on the computer terminals per student at a local university, data were collected from a sample of 64 business students over a one-week period. Assume the population standard deviation is 1.3 hours. 8. Refer to Exhibit 8-1. The standard error of the mean is a. 8.375 b. 0.8375 c. 0.1625 d. 0.0203 ANSWER: c 9. Refer to Exhibit 8-1. With a 0.95 probability, the margin of error is approximately a. 0.84 b. 1.645 c. 0.32 d. 1.96 ANSWER: c 10. Refer to Exhibit 8-1. If the sample mean is 10 hours, then the 95% confidence interval is approximately a. 8.36 to 11.36 hours b. 8.74 to 9.26 hours c. 9.16 to 10.84 hours d. 9.68 to 10.32 hours ANSWER: d Exhibit B A random sample of 144 automobiles traveling on a section of an interstate showed an average speed of 60 mph. The distribution of speeds of all cars on this section of highway is normally distributed, with a standard deviation of 14.9 mph....
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- Spring '10