A random sample of 23 items is drawn from a population whose standard deviation is unknown. The sample mean is xx = 770 and the sample standard deviation is s = 25. Use Appendix D to find the values of Student's t. (a) Construct an interval estimate of with 95% confidence.(Round your answers to 3 decimal places.)

(b) Construct an interval estimate of with 95% confidence, assuming that s = 50. (Round your answers to 3 decimal places.)

(c) Construct an interval estimate of with 95% confidence, assuming that s = 100. (Round your answers to 3 decimal places.)