A random sample of 21 items is drawn from a population whose standard deviation is unknown. The sample mean is = = 910 and the sample standard deviation is s = 20. Use Appendix D to find the values of Student's [ () Construct an Interval estimate of p with 99% confidence. (Round your answers to 3 decimal places.) The 99% confidence Interval is from to (b) Construct an Interval estimate of p with 99% confidence, assuming that s= 40. (Round your answers to 3 decimal places.) The 99% confidence Interval is from (c) Construct an Interval estimate of p with 99% confidence, assuming that s= 80. (Round your answers to 3 decimal places.) The 99% confidence Interval is from to (d) Describe how the confidence interval changes as s Increases. O The Interval stays the same as s Increases, The Interval gets wider as s Increases. The Interval gets narrower as s Increases