HW9_skeleton

9.2

• 1. Decreases
• 2. False, it is centered at 0.
• 3. Alpha.
• 4. True.
• 5. False, the population does not have to be approximately normal if the sample size is greater than 30.
• 6. Robust.
• 1. 1.316

  2. 1.697

  3. 2.552

  4. 1.725

9. yes.

• 1. 2.205

  2. 1.309

  3. 1.943

  4. 2.120

• 13. Point Estimate= 21, Margin of Error=3
• 14. Point Estimate= 25, Margin of Error= 5
• 1. Lower Bound= 103.656, Upper Bound= 112.344

  2. Lower Bound= 101.131, Upper Bound= 114.868, The margin of error increases.

  3. Lower Bound= 104.578, Upper Bound= 111.422, The margin of error decreases.

  4. No, the sample size would be too small.

• 1. Unreasonable, 95% is the level of confidence, not the probability.

  2. Reasonable.

  3. Unreasonable, 95% is the level of certainty, the percent of workers.

  4. Unreasonable, the survey was conducted says nothing about Idaho specifically.

• 29. We are 95% confident that the number of licks it takes to get the the center of a tootsie pop is between 317.630 and 394.569.
• 30. We are 90% confident that the number of books read all the through or part of the way through in a year by Americans is between 12.05 and 14.75.

9.3

• 1. False.
• 2. True.
• 3. False.
• 4. True.
• 5. 10.117, 30.144
• 6. 12.401, 39.364
• 1. Lower Bound= 7.942, Upper Bound= 23.663

  2. Lower Bound= 12.122, Upper Bound= 36.117, the width of the interval decreases.

  3. Lower Bound= 6.615, Upper Bound 31.364, the width of the interval increaseses.

• 11. Lower Bound= 0.226, Upper Bound= 0.542, We are 95% confident that the pH of rainwater in Tucker County, West Virginia will be btween 0.226 and 0.542.