As the class of 2012 celebrates the end of college, for many the promise of a college degree has turned to disappointment as they find themselves struggling to find a job (Financial Times, June 1, 2012). It is especially disturbing since recent evidence suggests that graduating at bad economic times can impact the person’s earning power for a long time. An associate dean at a prestigious college wants to determine if the starting salary of his college graduates has declined from 2008 to 2010. He expects the variance of the salaries to be different between these two years. The accompanying table shows a portion of the salary data for 40 college graduates; the complete data set, labeled Starting_Salaries, can be found on the text website.
Salary 2008 ($) Salary 2010 ($)
: ........... :
Use the p-value approach, at the 5% significance level, to determine if the mean starting salary has decreased from 2008 to 2010. Describe your steps clearly.