F I L E (Use Excel) It is g e n e rally b elieved th a t a practical m ajo r such as business o r e n g in e e rin g can really p ay o ff fo r college gradu ates (C N N M o n e y .c o m , July 2 2 , 2 0 10). O th e r studies have show n th a t it is n o t ju st th e m ajo r b u t also h o w students perform , as m easured by their GPA, th a t influences their salaries. H enry Chen, an em ployee o f PayScale.com, w ants to m easure th e effect o f m ajor and GPA on starting salaries of grad u ates o f th e U niversity o f California a t Irvine. H e sam ples startin g salaries o f five g radu ates fo r a given GPA ran g e from th e schools o f business, e n g in e erin g , a n d social sciences. The sam ple data are show n in th e follow ing table; th e data can also be found on th e text w ebsite labeled ANO VA-Salaries.
GPA Business Engineering Social Sciences 3.5–4.0 68 70 44 54 66 52 78 62 66 80 56 42 58 72 72 3.0–3.5 48 66 48 76 54 48 60 70 58 48 52 56 64 64 38 <3.0 54 60 44 42 42 38 66 48 42 58 59 52 66 65 50

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? P-36