Determine Confidence Interval or Margin of Error
12. A study was commissioned to find the mean weight of the residents in certain town. The study found the mean weight to be 152 pounds with a margin of error of 9 pounds. Write a confidence interval for the true mean weight of the residents of the town.
13. A study by the department of education of a certain state was trying to determine the mean SAT scores of the graduating high school seniors. The study found that the mean SAT score was 454 with a margin of error of 27. Write a confidence interval for the true mean SAT score of the graduating high school seniors.
14. A survey was given to a random sample of the residents of a town to determine whether they support a new plan to raise taxes in order to increase education spending. The survey reported a confidence interval that between 75% and 83% of the residents supports the plan. What is the margin of error on the survey?
15. A study was commissioned to find the mean weight of the residents in certain town. The study found a confidence interval for the mean weight to be between 159 pounds and 173 pounds. What is the margin of error on the survey?
12. The confidence interval for the true mean weight of the residents of the town is 152 ± 9 pounds.
13. The confidence interval for the true mean SAT score of the graduating high school seniors is 454 ± 27.
14. The margin of error on the survey is (83% - 75%) / 2 = 4%.
15. The margin of error on the survey is (173 - 159) / 2 = 7 pounds.