title: “HW9_skeleton”

output: html_document

9.2

• 1. Decreases
• 2. False
• 3. Alpha
• 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. (xbar = 3, E = 21)
• 14. (xbar = 25, E = 5)
• 1. Lower bound = 103.66, upper bound = 112.34

  2. Lower bound = 100.42, upper bound = 115.58. Decreasing sample size increases the margin of error

  3. Lower bound = 46.26, upper bound = 111.42. Decreasing the confidence level decreases the margin of error.

  4. No, because the sample sizes (n) are not large enough.

• 1. This statement is incorrect because the interpretation implies that the population mean varies rather than the interval

  2. This statement is correct because there is an interval for the population mean

  3. The statement is incorrect becuase this interpretation makes an implication about the individuals rather than the mean

  4. This statement is incorrect because the interpretation should be about the mean number of hours worked by adult American, not about adults in Idaho.

• 29. (317.64-194.56). The is 95% confidence that the mean number of licks to the center of a tootsie pop is between 317.64 and 194.56
• 30. (12.049-14.75). We are 99% confident that the mean number of books that Americans read either all or part of during the preceding year.

9.3

• 1. False
• 2. True
• 3. False
• 4. True
• 5. 10.117, 30.144
• 6. 13.848, 32.852
• 1. (10.1117, 30.144), lower bound = 7.94, upper bound = 23.66

  2. (17.708, 42.557), lower bound = 8.59, upper bound = 20.63

  3. (7.633, 36.191), lower bound = 6.61, upper bound = 31.36

• 11. (s2 = 0.102, x0.975^2 = 3.816 and x0.025^2 = 21.920) Lower bound = 0.226, upper bound = 0.542