Suppose the National Center for Education Statistics would like to investigate the effect that the education level for high school teachers and the state that employs them have on their salaries. Excel file high school salaries. xlsx contains salaries for a random sample of high school ­teachers from Colorado, Kansas, Minnesota, and Nebraska. The educational level for these teachers is also indicated in the file.

a. Using α = 0.05, is there significant interaction between the education level and the state?

b. Does the education level of the teacher have an effect on his or her salary?

c. Using a two way ANOVA and α = 0.05, does the state that employs the teacher have an effect on his or her salary?

d. If warranted, determine which means are significantly different using α = 0.05.

e. Construct an interaction plot for the education level and the state.