Repeat Exercise 11-60 using an error term with a standard deviation of 4. What impact has increasing the error standard deviation had on the values of R²?

(a) Fit the linear regression model by least squares and find the estimates of the slope and intercept.
(b) Find the estimate of σ².
(c) Find the value of R².
(d) Now use software to generate a new sample of eight observations, one each at the levels of x= 10, 14, 18, 22, 26, 30, 34, and 38. Fit the model using least squares.
(e) Find R² for the new model in part (d). Compare this to the value obtained in part (c). What impact has the increase in the spread of the predictor variable xhad on the value?