Signals Notebook: Why do some analytics definitions use the same expression?

Starting with Signals Notebook version 26.8, Signals fits linear concentration data using new system Agonist and Antagonist dose-response models. However, some analytical definitions of antagonist/agonist use the same expression (such as "Lin. Conc vs Response with Variable Slope, Antagonist" and "Lin. Conc vs Response with Variable Slope, Agonist"). Why do these definitions use the same expression?

Answer: The distinction between the antagonist and agonist models is the sign of the fitted slope: negative for the antagonist model and positive for the agonist model. Depending on the scenario, the fitting algorithm internally focuses its search on a solution space with either a positive or a negative slope. That said, both cases use the same formula. However, the equation’s symbol is applied internally to the slope, as these represent two different processes.