Is there a way to fix the lower asymptote (parameter c) at 0 in the Logistic 4p Hill model in Fit Curve? Basically, I want the 3-parameter version of the Logistic hill model.
Doesn't look doable in the Fit Model platform. Definitely doable in the Nonlinear platform. In the model library of the nonlinear platform choose Logistic 4p. Then select "Make Formula" to create the formula in a column. Then go to that column and alter the parameters and/or formula be as needed to be the Log 4p Hill model. You can just remove "c" parameter from the model, or leave it in and set it to 0 when you run the non linear model.
Have you tried the Logistic 3P model in Fit Curve? I do not have a good example of data for such a model, but it looks like this:
Thanks! I didn't even know you could do that! Also this blog post helped https://community.jmp.com/t5/JMPer-Cable/Nonlinear-modeling-part-3/ba-p/42506
