A random sample of 25 items is drawn from a population whose standard deviation is unknown. The sample mean is x¯ = 830 and the sample standard deviation is s = 5. Use Appendix D to find the values of Student’s t. (a) Construct an interval estimate of μ with 95% confidence. (Round your answers to 3 decimal places.) The 95% confidence interval is from ? to ?
A random sample of 25 items is drawn from a population whose standard deviation is unknown. The sample mean
is
x¯ = 830 and the sample standard deviation is s = 5. Use Appendix D to find the values of Student’s t.
(a) Construct an interval estimate of μ with 95% confidence. (Round your answers to 3 decimal places.)
The 95% confidence interval is from ? to ?
(b) Construct an interval estimate of μ with 95% confidence, assuming that s = 10. (Round your answers to 3 decimal places.)
The 95% confidence interval is from ? to ?
(c) Construct an interval estimate of μ with 95% confidence, assuming that s = 20. (Round your answers to 3 decimal places.)
The 95% confidence interval is from ? to ?
(d) Describe how the confidence interval changes as s increases.