HW8_skeleton

9.1

• 1. Point estimate.
• 2. Level of confidence, (1-alpha).
• 3. False.
• 4. Critical value.
• 5. Increases.
• 6. Decreases.
• 7. 1.645.
• 8. 2.575.
• 9. 2.33.
• 10. 1.75.
• 11. P(hat)=0.225, ME=0.024, X=270.
• 12. P(hat)=0.0625, ME=0.0115, X=70.
• 15. 0.146, 0.254.
• 16. 0.319, 0.481.
• 21. C is correct. A is false because there is no interval concerning the population proportion. B is false because there cannot be a varying confidence level. D is false because the interval does not set the standard for all other intervals.
• 1. 0.181.

  2. 341.59 is greater than or equal to 10 and the sample size is less than 5% of the population.

  3. 0.168, 0.194.

  4. There is 90% confidence that the proportion of American adults 18 years or older who donated blood in the past 2 years is between 0.168 and 0.194.

• 1. 0.43.

  2. 82.63 is greater than or equal to 10 and the sample size is less than 5% of the population.

  3. 0.401, 0.459.

  4. There is 95% confidence that the proportion of workers and retirees in the U.S. 25 years or older who have less than $10,000 in savings is between 0.401 and 0.459.