Primary Teacher Salary. Use the dataset Primary Teacher Salary to consider a primary school teacher’s average annual salary (in dollars) (PTSal) with various measures like teacher’s age (Age), the number of days taught per school year (NumDay), the average number of students per class (NumStu), and the ratio of students to teaching staff (%) (Ratio) for select 17 countries. Find a regression model for PTSal with Age and two other predictor variables to determine possible models.

a) Which model appears to do the best?

b) Would you leave all three predictors in this model?

c) Does this model mean that by changing the predictors in this equation, it would affect a primary school teacher’s average annual salary in a particular country? Explain.

d) Be sure to check the conditions for multiple regression.

What do you conclude?