How to do No. 12?

11. Suppose we have a dataset with five predictors, X1 = GPA, X2 = IQ, X3 = Gender (1 for Female and 0 for Male), X4 = Interaction between GPA and IQ, and X5 = Interaction between GPA and Gender. The response is starting salary after graduation (in thousands of dollars). Suppose we use least squares to fit a linear model and get Bo = 50, B1 = 20, B2 = 0.07, B3 = 35, B4 = 0.01, and 35 = 10. Which of the following statements is correct? (A) For a fixed value of IQ and GPA, males earn more on average than females. (B) For a fixed value of IQ and GPA, females earn more on average than males. (C) For a fixed value of IQ and GPA, females earn more on average than males provided that the GPA is high enough. (D) For a fixed value of IQ and GPA, males earn more on average than females provided that the GPA is high enough. 12. (Continuation) The predicted salary of a male with an IQ of 100 and a GPA of 3.0 is (A) $100,000 (B) $110,000 (C) $120,000 (D) None of the above