Re: [R] effect size

From: Bruno L. Giordano <bruno.giordano_at_music.mcgill.ca>
Date: Thu 22 Jun 2006 - 08:36:13 EST

For ANOVA one option is the partial eta squared \eta^2_p:

\eta^2_p=SSeffect/(SSeffect+SSerror)

For multiple regression (continuous predictors) you might use the standardized parameter estimate, the regression coefficient you obtain standardizing the predictor: the larger the absolute value, the larger the size of the effect.

You might take a look at:

S. Olejnik and J. Algina, (2003), Generalized eta and omega squared statistics: measures of effect size for some common research designs, Psychol Methods. 8(4):434-47.

and, if you have repeated measures:

R. Bakeman (2005), Recommended effect size statistics for repeated measures designs, Behavior Research Methods, 37 (3), 379-384.

    Bruno

> Does anyone know a simple way of calculating effect sizes?
>
> Thanks
> MB
>
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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Thu Jun 22 08:40:13 2006

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