Question: It is generally believed that a practical major such as business or engineering can really pay off for college graduates (CNN Money.com , July 22 , 2010). Other studies have shown that it is not just the major but also h o w students perform, as measured by their GPA, that influences their salaries. Henry Chen, an employee of PayScale.com, w ants to measure the effect of major and GPA on starting salaries of graduates of the University of California at Irvine. He samples starting salaries of five graduates for a given GPA ran g e from the schools of business, engineering, a n d social sciences. The sample data are shown in the following table; the data can also be found on the text website labeled ANO VA-Salaries.
a. At the 5% significance level, is there interaction between major and GPA?
b. At the 5% significance level, can you conclude that starting salary differs between majors?
c. At the 5% significance level, can you conclude that starting salary depends on GPA?