Question 8.55

55. Increasing Confidence. A random sample of is drawn from a normal population in which . The sample mean is . For (a)-(c), construct and interpret confidence intervals for with the indicated confidence levels. Then answer the question in (d).

  1. 90%
  2. 95%
  3. 99%
  4. What can you conclude about the width of the interval as the confidence level increases?

8.1.55

(a) (9.342, 10.658) (b) (9.216, 10.784) (c) (8.9696, 11.0304) (d) It increases.