Answers To Review W S
- 1. Answers to Review WS (1-7) Review for Ch 19 -22 TEST
- 2. WS #1 Conditions are met. Be sure to write formulas and plug in to check. Formula for confidence interval: Interval: (-.2146, .05462) We are 90% confident that the difference in proportion of those favoring the church proposal between the 25- 40 year age group and the 40 – 60 year age group is in the interval -.21 to .05.
- 3. WS #2 Assumptions are met.
- 4. WS #3 Notes: Always round up when reporting n. In this problem we had some idea what p should be. Many times we do not. If we don’t know then use 0.5 for p.
- 5. WS #4 Fail to reject the null since p-value is greater than alpha = .05. There is no evidence to suggest that the proportion of freshmen placed on academic probabation is less than 45%. p is proportion of freshmen placed on academic probation. Assumptions are all met – be sure to write formulas and plug in values to check. Be sure to write formula!
- 6. WS #5 Assumptions not met. Sample size is too small for np>10
- 7. WS #6 p1 is proportion of urban high school students who plan to pursue a post-secondary education. P2 is proportion of suburban high school students who plan to pursue a post-secondary education. Conditions are met, be sure to list and check these! Fail to reject the null since p-val is > than alpha =.05. There is no evidence to suggest that the two proportions between urban and suburban high school students who plan to pursue a post-secondary education are different.
- 8. WS #7 P is proportion of explosives found. All conditions are met. Be sure to list and check all conditions. Fail to reject null since p-val is > alpha = .05. There is no significant evidence to suggest the hand held sensor finds explosives more than 25 percent of the time.