# Question

Refer to Exercise 8.3. Assume that recent wedding costs in the United States are normally distributed with a standard deviation of $8100.

a. Determine a 95.44% confidence interval for the mean cost, μ, of all recent U.S. weddings.

b. Interpret your result in part (a).

c. Does the mean cost of all recent U.S. weddings lie in the confidence interval you obtained in part (a)? Explain your answer.

a. Determine a 95.44% confidence interval for the mean cost, μ, of all recent U.S. weddings.

b. Interpret your result in part (a).

c. Does the mean cost of all recent U.S. weddings lie in the confidence interval you obtained in part (a)? Explain your answer.

## Answer to relevant Questions

In each part, explain the effect on the margin of error and hence the effect on the precision of estimating a population mean by a sample mean. a. Increasing the confidence level while keeping the same sample size. b. ...Answer true or false to each statement concerning a confidence interval for a population mean. Give reasons for your answers. a. The length of a confidence interval can be determined if you know only the margin of error. b. ...In Exercise 8.35, you found a 95% confidence interval of 18.8 months to 48.0 months for the mean duration of imprisonment, μ, of all East German political prisoners with chronic PTSD. a. Determine the margin of error, E. b. ...For a fixed confidence level, show that (approximately) quadrupling the sample size is necessary to halve the margin of error. (Hint: Use Formula 8.1 on page 321.) For a t-curve with df = 8, find each t-value, and illustrate your results graphically. a. The t-value having area 0.05 to its right b. t0.10 c. The t-value having area 0.01 to its left (A t-curve is symmetric about 0.) d. ...Post your question

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