9.1

25.

  1. p hat = 0.181

  2. 341.84 is greater than 10, the sample is less than 5% of the population

  3. Lower bound = 0.168 Upper bound = 0.194

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

26.

  1. p hat = .4302

  2. 213.38 is greater than 10, the sample size is less than 5%

  3. (4015,4585)

  4. 95% confident

27.

  1. p hat = 0.519

  2. 250.39 is greater than 10, sample is less than 5% of the population

  3. lower bound= 0.488 uppwe vouns =0.550

  4. It is possible that the population proprtion is more than 60%, because it is possible that the true proportion is not captured in the confidence interval. However, it is not likely because 0.6 is outside of the confidence interval

  5. 1-0.550 = 0.450 1-0.488= 0.512

28.

  1. p hat = .7500

  2. 192 is greater than 10, the sample is 5% less than the population

  3. .7500 + 2.71 `.7500 - 2.71

  4. 99% confident

  5. 1 - 0.550 1-0.488

29.

  1. p hat = 0.111 Lower bound: 0.071 Upper bound: -.151

  2. Lower bound: 0.058 Upper bound: 0.164

  3. Increasing the confidence level increases the margin of error