(Data file: salary-gov) The data file gives the maximum monthly salary for 495 nonunionized job classes in a mid-western governmental unit in 1986. The variables are described in Table 5.9.   Examine...

(Data file: salary-gov) The data file gives the maximum monthly salary for 495 nonunionized job classes in a mid-western governmental unit in 1986. The variables are described in Table 5.9.

Examine the scatterplot of Max Salary versus Score, and verify that simple regression provides a poor description of this figure.

Fit the regression with response Max Salary and regressors given by B-splines, with d given by 4, 5, and 10. Draw the fitted curves on a figure with the data and comment.