The nonlinear model used in relating ln(Y ) to the treatment variables in the combined 1981–1984 data, equation 16.11, was fit using the derivative-free method. Convergence was slow because of the...

The nonlinear model used in relating ln(Y ) to the treatment variables in the combined 1981–1984 data, equation 16.11, was fit using the derivative-free method. Convergence was slow because of the large number of parameters in the model. Refit the model using one of the methods requiring derivatives. Use the same starting values used in the text. Was convergence obtained or assumed? How many iterations were required? Does the solution agree with that from the derivative-free method? Does it appear reasonable from these results to set γ = 1? On what do you base your answer?