6 A Statistics Teacher Started Class One Day By Drawing The Names Of 10 Students Out Of A Hat And Asked Them To Do As M 1 (47.96 KiB) Viewed 39 times
6 A Statistics Teacher Started Class One Day By Drawing The Names Of 10 Students Out Of A Hat And Asked Them To Do As M 2 (35.42 KiB) Viewed 39 times
6. A statistics teacher started class one day by drawing the names of 10 students out of a hat and asked them to do as many pushups as they could. The 10 randomly selected students averaged 15 pushups per person with a sample standard deviation of 9 pushups. Suppose the distribution of the population of number of pushups that can be done is approximately normal. The 95% confidence interval for the true mean number of pushups that can be done is a. 5.75 to 24.25. b.8.56 to 21.44 c. 11.31 to 18.55. d. 13.02 to 16.98 7. A sample of 37 AA batteries had a mean lifetime of 584 hours. A 95% confidence interval for the population mean was 579.2 <u<588.8. Which statement is the correct interpretation of the results? a. We are 95% confident that the interval of 579.2 hours and 588.8 hours might contains the population mean. b. The probability that the population mean is between 579.2 hours and 588.8 hours is 0.95. C. 95% of the light bulbs in the sample had lifetimes between 579.2 hours and 588.8 hours. d. None of these statements correctly interpret the results. 8. In a random sample of 400 registered voters, 120 indicated they plan to vote for a President. Determine a 95% confidence interval for the proportion of all the registered voters who will vote for the President. a. (0.25, 0.34) b. (0.27, 0.32) c. 10.29,0.30) d. Cannot be determined from the information given. 9. A sample of 225 elements from a population with a standard deviation of 75 is selected. The sample mean is 180. The 95% confidence interval for wis a. 105 to 225. b. 175 to 185 c. 171.78 to 188.22 d. 170.2 to 189.8. 10. The sample size needed to estimate population mean to provide a margin of error of 2 or less with a 95 probability when the population standard deviation equals 11 is a 10 b. 11. c. 126. d. 117 11. We are interested in conducting a study to determine the percentage of voters of a state would vote for the incumbent governor. What is the minimum sample size needed to estimate the population proportion with a margin of error of .05 with 95% confidence? a. 200 b. 100. C. 58 d. 385.
2. A statistics teacher started class one day by drawing the names of 10 students out of a hat and asked them to do as many pushups as they could. The 10 randomly selected students averaged 15 pushups per person with a standard deviation of 9 pushups. Suppose the distribution of the population of number of pushups that can be done is approximately normal. What is the standard error of the mean? a. 0.900 b.2.876 C. 3,061 d. 4.743 3. If the expected value of the sample statistic is equal to the population parameter being estimated, the sample statistic is said to a. have low variability b. be an unbiased estimator of the population parameter. c. have high precision d. be a random estimator of the population parameter. 4. For a population with an unknown distribution, the form of the sampling distribution of the sample mean is a, approximately normal for small sample sizes. b. exactly normal for large sample sizes. C. exactly normal for small sample sizes. d. approximately normal for large sample sizes 5. The CEO of a company wants to estimate the percent of employees that use company computers to go on Facebook during work hours with 95% confidence. He selects a random sample of 150 of the employees and finds that 53 of them logged onto Facebook that day. What is the estimate of the standard error of the proportion proportion ? a. 0.039 b. 0.050 c. 0.350 d. 0.455
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