HW8_skeleton

9.1

• 1. point estimate
• 2. level of confidence/(1-a)x100%
• 3. F
• 4. critical value
• 5. increases
• 6. decreases
• 7. 1.28
• 8. 2.33
• 9. 2.05
• 10. 1.40
• 11. p-hat=0.225, E=0.024, x=270
• 12. p-hat=0.0625, E=0.0115, x=70
• 15. lower bound:0.146, upper bound:0.254
• 16. lower bound:0.319, upper bound:0.481

1. There is no interval provided
2. Margin of error is applied to the level of confidence instead of applied to the point of estimate
3. This is correct.
4. The standard for all the other intervals will be the same.

• 1. p-hat=0.181

  2. np-hat(1-p-hat)=341.8>=10, n<=5%N

  3. lower bound=0.168, upper bound=0.194

  4. we are 90% confident that the proportition of adult Americans 18 years and older who have donated blood in the past two years is between 0.168 and 0.194

• 1. p-hat=0.43

  2. np-hat(1-p-hat)=282.6>=10, n<=5%N

  3. lower bound=0.402, upper bound=0.459

  4. we are 95% confident that the proportition of workers and retirees in the Us 25 years of age or older who have less than 10,000 in saving is between 0.402 and 0.459