Creatinine clearance (Y) is an important measure of kidney function, but is difficult to obtain in a clinical office setting because it requires 24-hour urine collection. To determine whether this measure can be predicted from some data that are easily available, a kidney specialist obtained the data that follow for 33 male subjects. The predictor variables are serum creatinine concentration (X1), age (X2), and weight (X3) a. Prepare separate dot plots for each of the three predictor variables. Are there any noteworthy features in these plots?
Comment.
b. Obtain the scatter plot matrix. Also obtain the correlation matrix of the X variables. What do the scatter plots suggest about the nature of the functional relationship between the response variable Y and each predictor variable? Discuss. Are any serious multicollinearity problems evident? Explain.
c. Fit the multiple regression function containing the three predictor variables as first order terrns. Does it appear that all predictor variables should be retained?