HW8_skeleton

9.1

• 1. point estimate
• 2. level of confidence (1-alpha) 100%
• 3. false
• 4. critical value
• 5. increases
• 6. decreases
• 7. 1.645
• 8. 2.575
• 9. 2.364
• 10. 1.662
• 11. p hat=0.225 margin of error=0.024 x=270
• 12. p hat=0.0625 margin of error=0.0115 x=70
• 15. (0.134, 0.266)
• 16. (0.318, 0.48)
• 21. 1. flawed because nothing about the population proportion was given
  2. flawed - shows that the level of confidence is different
  3. correct
  4. flawed - shows that this is standard for all intervals which isn’t true
• 1. p hat=0.182

  2. 341.8 is greater than 10 and the sample is less than 5% of the population

  3. (0.168,0.194)

  4. We are 90% confident that the proportion of the adult Americans 18 years or older who have donated blood in the past 2 years is between 0.168 and 0.194

• 1. p hat=0.43

  2. 282.6 is greater than 10 and the sample is less than 5% of the population

  3. (0.403, 0.457)

  4. We are 95% confident that the proportion of workers and retirees in the US 25 years old and older is between 0.403 and 0.457.