A random sample of 25 items is drawn from a population whose standard deviation is unknown. The sample mean is x⎯⎯x¯ = 850 and the sample standard deviation is s = 15. Use Appendix D to find the values of Student’s t. (a) Construct an interval estimate of μμ with 95% confidence. (Round your answers to 3 decimal places.) The 95% confidence interval is from ____to__ (b) Construct an interval estimate of μμ with 95% confidence, assuming that s = 30. (Round your answers to 3 decimal places.) The 95% confidence interval is from ___to__ (c) Construct an interval estimate of μμ with 95% confidence, assuming that s = 60. (Round your answers to 3 decimal places.) The 95% confidence interval is from __ to __ (d) Describe how the confidence interval changes as s increases.
A random sample of 25 items is drawn from a population whose standard deviation is unknown. The sample mean is
= 850 and the sample standard deviation is s = 15. Use Appendix D to find the values of Student’s t.
(a) Construct an
with 95% confidence. (Round your answers to 3 decimal places.)
The 95% confidence interval is from ____to__
(b) Construct an interval estimate of
with 95% confidence, assuming that s = 30. (Round your answers to 3 decimal places.)
The 95% confidence interval is from ___to__
(c) Construct an interval estimate of
with 95% confidence, assuming that s = 60. (Round your answers to 3 decimal places.)
The 95% confidence interval is from __ to __
(d) Describe how the confidence interval changes as s increases.
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