Chapter 9.2, Problem 25AYU

Hours Worked Revisited For the ”Hours Worked” survey conducted by Gallup in Problem 21, provide two recommendations for increasing the precision of the interval.

21. You Explain It! Hours Worked In a survey conducted by the Gallup Organization, 1100 adult Americans were asked how many hours they worked in the previous week. Based on the results, a 95% confidence interval for mean number of hours worked was lower bound: 42.7 and upper bound: 44.5. Which of the following represents a reasonable interpretation of the result? For those that are not reasonable, explain the flaw.

1. a. There is a 95% probability the mean number of hours worked by adult Americans in the previous week was between 42.7 hours and 44.5 hours.
2. b. We are 95% confident that the mean number of hours worked by adult Americans in the previous week was between 42.7 hours and 44.5 hours.
3. c. 95% of adult Americans worked between 42.7 hours and 44.5 hours last week.
4. d. We are 95% confident that the mean number of hours worked by adults in Idaho in the previous week was between 42.7 hours and 44.5 hours.