HW9_skeleton

9.2

• 1. Decreases
• 2. False
• 3. a
• 4. True
• 5. False
• 6. Robust
• 1. 1.316

  2. 1.697

  3. -2.552

  4. 1.725

• 1. 2.205

  2. 1.309

  3. -1.943

  4. 2.120

• 13. 21, 1.5
• 14. 25,5
• 1. Lower bound 103.656 - Upper bound 112.344

  2. Lower bound 100.416 - Upper bound 115.583. The margin of error gets bigger when the sample size is smaller.

  3. Lower bound 104.578 - Upper bound 111.422 The margin of error gets smaller when the level of confidence decreases

  4. Only if the sample sizes were bigger.

• 1. No because it is the interval that is changing

  2. Correct

  3. Wrong because we are 95 % confident that the mean was between the interval not that the americans actually worked between the interval

  4. Wrong because the sample was not specifically from Idaho

• 29. We are 95 % confident, that the mean number of licks to the center of a Tootsie Pop is between 317.630 and 394.569
• 30. We are 99 % confident, that the mean number of books that Americans read either all or part of during the preceding year is between 12.05 and 14.75

9.3

• 1. False
• 2. True
• 3. False
• 4. False
• 5. 10.117 and 30.144
• 6. 12.401 and 39.364
• 1. Lower bound 7.941 - upper bound 23.663

  2. Lower bound 8.586 - upper bound 20.634. When the sample size increases the width of the interval decreases.

  3. Lower bound 6.615 - upper bound 31.363. When the confidence level increases the width of the interval increase.

• 11. We are 95 % confident, that the standard deviation PH of rainwater in Tucker County, West Virginia is between 0.226 and 0.542