Converting concentration to log(concentration)

 Print this Topic

Transforming X values with Prism

All the dose-response equations built-in to Prism expect the X values to be the logarithm of dose or concentration.

If you entered actual doses or concentrations, instead of their logarithms, use Prism to transform the X values.

1.From the data table, click Analyze and then choose Transform, which is the very first analysis listed on the Analyze dialog.
2.On the Transform dialog, check the option to transform X, and choose X=log(X) .At the bottom of the dialog, check the option: Create a new graph of the results.

3. Go to the newly created graph.
4.Click Analyze, choose nonlinear regression, and then choose the dose-response curve.

 

 


Copyright (c) 2007 GraphPad Software Inc. All rights reserved.
URL: http://www.graphpad.com/help/Prism5/Prism5Help.html?reg_dose_or_logdose.htm