Fit Curve Model Formulas provides the formulas for the models on the Fit Curve red triangle menu.
where k is the order of the polynomial. These models can also be fit using the Fit Model and Fit Y by X platforms.
a = Growth Rate
b = Inflection Point
a = Growth Rate
b = Inflection Point
c = Asymptote
a = Growth Rate
b = Inflection Point
c = Lower Asymptote
d = Upper Asymptote
a = Growth Rate
b = Inflection Point
c = Asymptote 1
d = Asymptote 2
f = Power
a = Asymptote
b = Growth Rate
c = Inflection Point
a = Lower Asymptote
b = Upper Asymptote
c = Growth Rate
d = Inflection Point
a = Scale
b = Growth Rate
a = Asymptote
b = Scale
c = Growth Rate
a = Scale 1
b = Decay Rate 1
c = Scale 2
d = Decay Rate 2
a = Asymptote
b = Scale 1
c = Decay Rate 1
d = Scale 2
f = Decay Rate 2
a = Asymptote
b = Scale
c = Growth Rate
a = Peak Value
b = Critical Point
c = Growth Rate
a = Peak Value
b = Growth Rate
c = Critical Point
a = Area Under Curve
b = Elimination Rate
c = Absorption Rate
α =
β =
a = Initial Concentration
b = Transfer Rate In
c = Transfer Rate Out
d = Elimination Rate
a = Max Reaction Rate
b = Inverse Affinity
Parallelism Test
Gives the relative potencies. There is a report for each level of the grouping variable. The relative potency is exp(EC50), where EC50 is the point at which the middle response value is obtained. For the Logistic 2P, 3P, and 4P, the relative potency is exp(inflection point parameter).
Parameter Comparison for Growth Rate Estimates
The Equivalence Test report gives an analysis for testing the equivalence of models across levels of the grouping variable (Equivalence Test). After selecting the option, you specify the level of the grouping variable that you want to test against every other level. There is a report for every level versus the chosen level. Select Equivalence Test from the fitted model’s red triangle menu to add the report.
Equivalence Test