4 parameter logistic curve graphpad prism

The Y value of the curve when X is the value entered within the brackets. If an interpolation is included in the definition, the interpolation can be based on a constant value (a number), a single parameter, or a combination (function) of multiple parameters. The interpolated value and its confidence interval (if applicable) will appear in the results along with other transformed parameters. You can also use the “Transforms” controls to report values calculated from the curve of best-fit parameter values. Enter the label “Half Life” in the left text box and enter the definition “ln(2)/K” in the right text box (without the quotes). Enter the label “EC50” in the left text box and enter “10^logEC50” in the right text box (without the quotes).Įxample : You fit data to an equation that reports a rate constant “K”, but you would also like to report the half-life. Because these definitions are for transformations of parameters, it would make no sense to include X or Y in the transform (although interpolations can be used).Įxample : you fit data to an equation that includes the parameter “logEC50” that is the logarithm of an EC50, but you also want to include a value and error estimate for the EC50 based on the best-fit model parameter values. The inputs to the transform can only be parameters fit by the regression or standard mathematical operators (log, exp, etc.). However, you cannot use the result of one transformation as the input for another. Note that you can use any combination of model parameters when defining the transformation. The second text box on each row of the dialog is for the definition (equation) that will be used to calculate the desired transformation or interpolation. Define the transformation or interpolation

This is the name that will be displayed in the table of results for the nonlinear regression, so choose something that you’ll recognize. The far left text box on each row of the Transforms to Report dialog is used to name the transformation for that row. Using the 'Transforms to Report' tab of the model definition dialog, these values can be defined for Prism to report (along with their confidence intervals when applicable) on the reported results.ĭefining parameter transformations Give the transformation a name While fitting a nonlinear regression model, you may also be interested in various transformations, combinations, and interpolations of the best-fit parameter values.

4 parameter logistic curve graphpad prism