HW8_skeleton

9.1

• 1. Point estimate.
• 2. Level of confidence.
• 3. False.
• 4. (1-α) 100%
• 5. Increases.
• 6. Decreases.
• 7. 1.645
• 8. 2.576
• 9. 2.326
• 10. 1.645 (this is for .05–closest to .04)
• 11. ^P= .225. E=.024. X=270
• 12. ^P= .0625. E=.0115. X=70
• 15. (.1462,.2537)
• 16. (.3195,.4804)

1. Not reasonable. The population proportion wasnt brought up

2. Not reasonable. It is 95% confidence with a margin or error of 3% but you cannot have various levels of confidence.

3. Correct. The margin error of 3% is applied.

4. Not reasonable. Its not 95% of samples but 95% confidence of this one sample.

• 1. P^=x/n=.1808

  2. 341.84 ≥ 10. Sample is less than 5% of the population.

  3. (1.68, .194)

  4. We are 90% confidence that the proportion of adults 18+ that have given blood in the past 4 years is between .168 and .194.

• 1. P^=.4301

  2. 282.6 ≥ 10. Sample is less than 5% of the population.

  3. (.401 ,.459)

  4. We are 95% confident that the proportion of workers and retirees in the US 25+ who have less than 10,000$ in savings is between .401 and .459