The data from Taiwo et al XXXXXXXXXXused in Case Study 7.1 is shown in Table 8.33. Convert the data to logarithms, y = ln(WATER) and x = ln(STIME ). (a) Fit a quadratic model, of the form y = β 0 + β...

The data from Taiwo et al. (1998) used in Case Study 7.1 is shown in Table 8.33. Convert the data to logarithms, y = ln(WATER) and x = ln(STIME ).

(a) Fit a quadratic model, of the form y = β₀
+ β₁x + β₂x²
+ ε.

(b) Modify the independent variable to create x* = ln(STIME) if STIME
 4, and x* = ln( 4) if STIME . 4. Fit the quadratic model using the new independent variable.

(c) Which model fits better?