Question: Question 2: Wharton School students who graduated in the class of 2005 were surveyed to obtain employment information. There were 625 graduates, but only 400 returned the survey. Sixty six respondents did not have a job at the time of the survey. The students without jobs were eliminated from the analysis of salary data.

Summary data in units of thousands of dollars: Average salary = 62.6; standard deviation = 7.4; n = 334.

A. Are the salaries sufficiently high to make the claim that the mean salary µ exceeds 60?

Use a=.01

B. One of the concerns of the study is that 225 graduates did not respond. Twenty of the non-respondents were called back and their salaries were recorded. These twenty non-respondents were matched (based on a variety of characteristics including major and location of job) to twenty from among the original 334 respondents.

Summary data of the differences between the salaries of the original respondents and the respondents who provided salaries after they were called back: Average=3.25; standard deviation=7.15; n=20.

Are these data sufficient in concluding that the mean salary of initial respondents is different from the mean salary of those who did not respond initially? Use a=.05