In: Statistics and Probability
A random sample of 14 items is drawn from a population whose standard deviation is unknown. The sample mean is x¯ = 780 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 98% confidence. (Round your answers to 3 decimal places.) The 98% confidence interval is from _ to _
(b) Construct an interval estimate of μ with 98% confidence, assuming that s = 10. (Round your answers to 3 decimal places.) The 98% confidence interval is from _ to _
(c) Construct an interval estimate of μ with 98% confidence, assuming that s = 20. (Round your answers to 3 decimal places.) The 98% confidence interval is from _ to _
Given that, sample size (n) = 14 and sample mean = 780
t-critical value at significance level of 0.02 with degrees of freedom = 14 - 1 = 13 is,
a) sample standard deviation (s) = 5
The 98% confidence interval for the population mean is,
The 98% confidence interval is from 776.459 to 783.541
b) sample standard deviation (s) = 10
The 98% confidence interval for the population mean is,
The 98% confidence interval is from 772.918 to 787.082
c) sample standard deviation (s) = 20
The 98% confidence interval for the population mean is,
The 98% confidence interval is from 765.835 to 794.165