[R] interaction plot in R for factorial experiment

John Fox jfox at mcmaster.ca
Sat Jan 31 19:40:14 CET 2009


Dear Swanton0822,

You could refit the model with the statistically significant high-order
terms and try plot(allEffects(mod)) from the effects package, where mod is
the model object. A caution, however: If you used the default "treatment"
contrasts for the factors, then a lower-order term such as dts, which is
marginal to the pdts interaction, isn't reasonably interpretable as a test
of the lower-order term, here the dts interaction.

I hope this helps,
 John

------------------------------
John Fox, Professor
Department of Sociology
McMaster University
Hamilton, Ontario, Canada
web: socserv.mcmaster.ca/jfox


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On
> Behalf Of Swanton0822
> Sent: January-31-09 11:46 AM
> To: r-help at r-project.org
> Subject: [R] interaction plot in R for factorial experiment
> 
> 
> hi,
> i did a 2^4 factorial experiment, and i got the following result:
> 
> 	Effect	                           t	         p (computer)
> 
> p	-484.52494328125	  -5.64590926071629	<0.0001
> d	-450.67095078125	  -5.25142684568607	<0.0001
> pd	438.80508046875	  5.11316022388923	0.0001
> t	351.87216640625	   4.1001776078805	0.0008
> pt	-341.05023984375	  -3.97407550262202	0.0011
> dt	-311.27784109375  -3.62715371015861	0.0023
> pdt	301.91850265625	 3 .51809435977593	0.0029
> s	-63.38395046875	 -0.73857917511704	0.4709
> ps	51.95851828125	 0.60544474253604	0.5534
> ds	59.97782328125	 0.69888940207698	0.4947
> pds	-50.13595796875	 -0.58420742485148	0.5672
> ts	-62.18328890625	 -0.7245885099744	0.4792
> pts	52.58411734375	 0.61273451283464	0.5487
> dts	58.99120359375	 0.68739285208981	0.5017
> pdts	-50.64764015625	 -0.5901697829117	0.5633
> 
> 
> and i want to plot those whose are significant in R for an interaction
plot
> to see their effect?
> but i don't know how to do it in R, all i know is using
'interaction.plot()'
> can anyone help me out what i need to put in for the plot?
> many thanks.
> 
> --
> View this message in context: http://www.nabble.com/interaction-plot-in-R-
> for-factorial-experiment-tp21765674p21765674.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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