Statistical Details for the Fit Curve Platform

Table 12.1 provides the formulas for the models on the Fit Curve red triangle menu.

Table 12.1 Fit Curve Model Formulas
Model	Formula
Polynomials	where k is the order of the polynomial. These models can also be fit using the Fit Model and Fit Y by X platforms.
Logistic 2P	a = Growth Rate b = Inflection Point Available only when all response values are between zero and one.
Logistic 3P	a = Growth Rate b = Inflection Point c = Asymptote
Logistic 4P	a = Growth Rate b = Inflection Point c = Lower Asymptote d = Upper Asymptote
Logistic 4P Rodbard	a = Growth Rate b = Inflection Point c = Lower Asymptote d = Upper Asymptote Available only when the regressor values are positive.
Logistic 4P Hill	a = Growth Rate b = Inflection Point c = Lower Asymptote d = Upper Asymptote
Logistic 5P	a = Growth Rate b = Inflection Point c = Asymptote 1 d = Asymptote 2 f = Power
Probit 2P	a = Growth Rate b = Inflection Point Φ = Normal Distribution CDF Available only when all response values are between zero and one.
Probit 4P	a = Growth Rate b = Inflection Point c = Asymptote 1 d = Asymptote 2 Φ = Normal Distribution CDF
Gompertz 3P	a = Asymptote b = Growth Rate c = Inflection Point
Gompertz 4P	a = Lower Asymptote b = Upper Asymptote c = Growth Rate d = Inflection Point
Weibull Growth	a = Upper Asymptote b = Growth Rate c = Inflection Point Available only when both the response values and regressor values are non-negative.
Exponential 2P	a = Scale b = Growth Rate
Exponential 3P	a = Asymptote b = Scale c = Growth Rate
Biexponential 4P	a = Scale 1 b = Decay Rate 1 c = Scale 2 d = Decay Rate 2 Available only when the response values are positive.
Biexponential 5P	a = Asymptote b = Scale 1 c = Decay Rate 1 d = Scale 2 f = Decay Rate 2
Mechanistic Growth	a = Asymptote b = Scale c = Growth Rate
Gaussian Peak	a = Peak Value b = Critical Point c = Growth Rate
Lorentzian Peak	a = Peak Value b = Growth Rate c = Critical Point
One Compartment Oral Dose	a = Area Under Curve b = Elimination Rate c = Absorption Rate Available only when the response values and the regressor values are all positive.
Two Compartment IV Bolus Dose	α = β = a = Initial Concentration b = Transfer Rate In c = Transfer Rate Out d = Elimination Rate Available only when the response values and the regressor values are all positive.
Michaelis-Menten	a = Max Reaction Rate b = Inverse Affinity Available only when the response values and the regressor values are all positive.