Coefficient of Determination or R^2

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I am a newbie to Igor Pro. I fit my data points using a built-in function and it worked fairly well. However, I don't know how to calculate the coefficient of determination or R^2. I looked through the instruction manual, but I could not find any information. I need your help.

Hak
alvysinger wrote:
... I don't know how to calculate the coefficient of determination or R^2. I looked through the instruction manual, but I could not find any information. I need your help.


See page III-202 of the manual for the discussion of V_Pr. It is returned as one of the coefficient to a CurveFit operation. An R^2 value only applies when doing linear regression fits. Its magnitude is also only of real use when comparing one linear model against others to fit the same data, not when comparing different data sets fit by the same linear model.

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J. J. Weimer
Chemistry / Chemical & Materials Engineering, UAH

April 28, 2009 at 01:36 pm - Permalink

jjweimer wrote:
alvysinger wrote:
... I don't know how to calculate the coefficient of determination or R^2. I looked through the instruction manual, but I could not find any information. I need your help.


See page III-202 of the manual for the discussion of V_Pr. It is returned as one of the coefficient to a CurveFit operation. An R^2 value only applies when doing linear regression fits. Its magnitude is also only of real use when comparing one linear model against others to fit the same data, not when comparing different data sets fit by the same linear model.

--
J. J. Weimer
Chemistry / Chemical & Materials Engineering, UAH


Thank you very much. Things are cleared up.

April 28, 2009 at 03:03 pm - Permalink