A school supervisor is reviewing initial wages of former students (in $000). Samples were taken over 3 years for four different majors (accounting, administration, finance, and marketing). For each combination of major and year, three former students were sampled.

a. Here is an interaction plot of the information. What does it reveal?

b. Write out all of the pairs of null and alternative hypotheses you would apply for a two-way ANOVA.
c. Here is the statistical software output. Use the 0.05 level to check for interactions.

d. If proper, test the other hypotheses at the .05 significance level. If it is not appropriate, describe why you should not do thetests.