I am studying the PD2-Inhibitory Imax model form Dr. Dan Weiner's textbook "PK&PD Data Analysis: concept and application". In dataset, the column0 is concentration and the column1 is blood pressure.
In this application the author wants to simulate differences in experimental error (constant CV) after fitting a dataset to PD 108 model (weighting=uniform, the values for Imax, IC50, n and E0 are 34.66, 139.6, 2.031 and 171.4, respectively). So the same dataset was fit with 0.5, 2, 3 or 5% constant CV.
First I tried the PD 108 model with different constant CV but the results were the same for different constant CV.
Then I tried Phoenix NLME. Type=Emax and check baseline, inhibitor and sigmoid. I chose residual error as mutiplicative and froze the SD as 0.005, 0.02, 0.03, and 0.05. But I still got similar results. Furthermore, there is no CV% for each parameter. (The results in the book show different mean estimates and precision CV%).
Could someone help me to figure it out? Please see the attachment. Thank you!