In particular, The Five Parameters Logistic Regression or ... the slope factor (Hill's slope). This curve is symmetrical around its inflection point. To extend the model to handle curves that are not ...

In particular, The Four Parameters Logistic Regression or 4PL nonlinear regression ... and the slope factor (Hill's slope). This curve is symmetrical around its inflection point. The 4PL equation is: ...

The coefficient of determination, or $R^2$, is a measure that provides information about the goodness of fit of a model. In the context of regression it is a ...