29.

a. Consider the data in Exercise 20. Suppose that instead of the least squares line passing through the points (x1, y1), . . . , (xn, yn), we wish the least squares line passing through (x1  , y1), . . . ,

(xn  , yn). Construct a scatter plot of the (xi, yi)

points and then of the (xi  , yi) points. Use the plots to explain intuitively how the two least squares lines are related to one another.

b. Suppose that instead of the model Yi  b0 

b1xi  ei(i  1, . . . , n), we wish to t a model of the form Yi  (xi )ei (i1, . . . , n).

What are the least squares estimators of and

, and how do they relate to and ?