C. Construct an interval estimate of u with 98% confidence, assuming that s=40. ( Round your answer to 3 decimal places).The 98% confidence interval is from ______ to______D. Describe how the confidence interval changes as s increases.A.The interval stays the same as s increases.B. The interval gets wider as s increases.C. The interval gets narrowed as s increases.

A random sample of 21 items is drawn from a population whose standard deviation is unknown. The sample mean is a = 750 and the sample standard deviation is s = 10. Use Appendix D to find the values of Student's t (a) Construct an interval estimate of // with 98% confidence. (Round your answers to 3 decimal places.) The 98% confidence interval is from to (b) Construct an interval estimate of / with 98% confidence, assuming that s = 20. (Round your answers to 3 decimal places.) The 98% confidence interval is from to