Reference no: EM132332051
1. The Ball Corporation's beverage can manufacturing plant in Fort Atkinson, Wisconsin, uses a metal supplier that provides metal with a known thickness standard deviation σ = .000952 mm. Assume a random sample of 59 sheets of metal resulted in an x¯ = .3354 mm.
Calculate the 99 percent confidence interval for the true mean metal thickness. (Round your answers to 4 decimal places.)
The 99% confidence interval is from to?
2. A random sample of 21 items is drawn from a population whose standard deviation is unknown. The sample mean is x¯ = 910 and the sample standard deviation is s = 20. Use Appendix D to find the values of Student's t.
(a) Construct an interval estimate of μ with 99% confidence. (Round your answers to 3 decimal places.)
The 99% confidence interval is from to?
(b) Construct an interval estimate of μ with 99% confidence, assuming that s = 40. (Round your answers to 3 decimal places.)
The 99% confidence interval is from to?
(c) Construct an interval estimate of μ with 99% confidence, assuming that s = 80. (Round your answers to 3 decimal places.)
The 99% confidence interval is from to?
3. A random sample of 16 pharmacy customers showed the waiting times below (in minutes).
17 18 16 20 20 12 19 19
15 27 14 23 15 25 18 20
Click here for the Excel Data File
Find a 90 percent confidence interval for μ, assuming that the sample is from a normal population. (Round your standard deviation answer to 4 decimal places and t-value to 3 decimal places. Round your answers to 3 decimal places.)
The 90% confidence interval __to__?