The National Association of Independent Colleges and Universities reported that students graduating from public colleges and universities have an average debt of $12,000 upon graduation (Kiplinger’s Personal Finance Magazine, November 1998). Assume that this average or mean amount is based on a sample of 245 students and that, based on past studies, the population standard deviation for the debt upon graduation is $2200. 1. Develop a 90% confidence interval estimate of the population mean. 2. Develop a 95% confidence interval estimate of the population mean 3. Develop a 99% confidence interval estimate of the population mean. 4. Discuss what happens to the width of the confidence interval as the confidence level is increased. Does this result seem reasonable? Explain. 5. Using a confidence interval of 90% we want our margin to be within $100, what is the minimum number of people I need to sample?
The National Association of Independent Colleges and Universities reported that students graduating from public colleges and universities have an average debt of $12,000 upon graduation (Kiplinger’s Personal Finance Magazine, November 1998). Assume that this average or
1. Develop a 90% confidence
2. Develop a 95% confidence interval estimate of the population mean
3. Develop a 99% confidence interval estimate of the population mean.
4. Discuss what happens to the width of the confidence interval as the confidence level is increased. Does this result seem reasonable? Explain.
5. Using a confidence interval of 90% we want our margin to be within $100, what is the minimum number of people I need to sample?
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