# Compute the standard error for each sample proportion. Compute and describe a 95% confidence… 1 answer below »

Case Study Has Gold Lost Its Luster? (Chapter Nine)

Please use ONLY one Excel file to complete case study one, and use one spreadsheet for each problem. Finally, email me the Excel file for grading. No credit will be granted for problems that are not completed using Excel.

In 2011, when the Gallup organization polled investors, 30% rated gold the best long-term investment. But in April of 2013 Gallup surveyed a random sample of U.S. adults. Respondents were asked to select the best long-term investment from a list of possibilities. Only 219 of the 875 respondents chose gold as the best long-term investment. By contrast, only 84 chose bonds.

a. Compute the standard error for each sample proportion. Compute and describe a 95% confidence interval in the context of the question.

b. Do you think opinions about the value of gold as a long-term investment have really changed from the old 30% favorability rate, or do you think this is just sample variability? Explain.

c. Suppose we want to increase the margin of error to 4%, what is the necessary sample size?

d. Based on the sample size obtained in part c, suppose 173 respondents chose gold as the best long-term investment. Compute the standard error for choosing gold as the best long-term investment. Compute and describe a 95% confidence interval in the context of the question.

e. Based on the results of part d, do you think opinions about the value of gold as a long-term investment have really changed from the old 30% favorability rate, or do you think this is just sample variability? Explain.

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