(20 points, 5 each) For this problem assume the simple linear regression model with an

intercept and predictor variable X,

Yi = 0 + 1Xi + i i = 1; 2; : : : ; n

(a) What are the normal equations for this model?

(b) List 3 assumptions we make on the residuals i. (c)(c) Show the residuals of the tted model sum to zero. If you use R to so this, write what the residuals sum to on your exam. (d)True or False: If the intercept 0 term is dropped, the residuals will still sum to zero?