Using the data of Exercise 14.99, 

In exercise

(a) Create a new variable, x₂². 

(b) Fit a surface of the form

(c) Find the correlation matrix of the three independent variables. Is there evidence of multi-collinearity? 

(d) Standardize each of the independent variables, x₁ and x₂, and create a new variable that is the square of the standardized value of x₂. 

(e) Fit a surface of the same form as in part (b) to the standardized variables. Compare the goodness of fit of this surface to that of the linear surface fitted in Exercise 14.99.

(f) Plot the residuals of this regression analysis against the values of  and compare this plot to the one obtained in Exercise 14.99.

Transcribed Image Text:

-63631-352-8254 x469 67 62 9 2 3 24 48 3 I- y-18 38 5 4 37 00 9952 8 135431049791 131 y = bo + bば1+b2X2 + b3X2,