[R] 3-way interaction simple slopes

Michael Friendly friendly at yorku.ca
Mon Nov 8 00:20:13 CET 2010


You would get more helpful replies if you indicated which among
MONTHS, CEXPOSE.M and bf.m were factors vs. covariates, and
for which factor or factors you wanted to test the simple slopes.

You will find that linearHypothesis in the car package can test these
things, and the effects package can produce visualizations of the
fitted model to help you understand these tests.

Maybe this will get you started:

library(effects)
tmod.effects <- allEffects(tmod)
plot(tmod.effects)

but you really just want to look tat the 3-way term.

On 11/6/2010 9:06 AM, Michael Wood wrote:
> Can anyone show me how to test for significant simple slopes of a 3-way
> interaction, with covariates.
>
> my equation
> tmod<-(glm(PCL~ rank.f + gender.f + MONTHS + CEXPOSE.M + bf.m +
> MONTHS*CEXPOSE.M*bf.m,
> data=mhatv, family=gaussian ,na.action=na.omit))
>
> Thank you
> Mike
>
> 	[[alternative HTML version deleted]]
>



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