Question

This assignment is designed to illustrate how a spreadsheet program such as Microsoft Excel supplemented by PHStat can enable you to easily accomplish hypothesis tests and confidence intervals that compare two population parameters. All work should be accomplished using PHStat. You should provide all the appropriate printouts of the tests you do and the confidence intervals you create along with explanations of the meaning of your answers and business implications for each problem. The assignment should be submitted to the drop box created for this purpose. Use the information in your text both within the chapter and at the end of the chapter and in the appendices at the end of the book as a guide to completing the assignment of needed.

You have been asked once again to study the mean tuition at private universities throughout the United States. You will also again study the proportions of universities throughout the United States that regularly award more than 50% of their students some form of financial aid. The specific questions you will be asked to answer are stated below. In addition, appropriate sample data for the studies you will be accomplishing is given below. Answer the following questions concerning the situations posed.

You first wish to know whether there is a difference in the mean tuition at private universities that are located east and west of the Mississippi River. The population standard deviation in the tuition of private universities east of the Mississippi is thought to equal $11,000, and the standard deviation in the tuition of private universities west of the Mississippi is thought to equal $10,000. A random sample of 25 private universities located east of the Mississippi River is chosen. The sample mean tuition for these universities is found to equal $19,850. A random sample of 35 universities located west of the Mississippi River is selected. The sample mean tuition for these universities is found to equal $14,765. At each of the 5% and 10% levels of significance, is there a difference in the mean tuition rates for these two groups of private universities? If at either level of significance, you do observe that there is a difference in the mean tuition, is that difference different from $2,000? If the software permits it, construct both 95% and 90% confidence intervals for the difference in the mean tuition for universities located east and west of the Mississippi River. Explain their meanings in the context of the problem. Use these intervals to test whether there is a difference in the mean tuition rates. Use the 95%

confidence interval to perform the test at the 5% level of significance and the 90% confidence interval to perform the test at the 10% level of significance.

Answer 1

for alpha = 0.05

for alpha = 0.10