Question 11.18

11.18 Understanding the fitted regression line.

The fitted regression equation for a multiple regression is

  1. If and , what is the predicted value of y?
  2. For the answer to part (a) to be valid, is it necessary that the values and correspond to a case in the data set? Explain why or why not.
  3. If you hold at a fixed value, what is the effect of an increase of two units in on the predicted value of ?