[R-sig-eco] Factors in partialRDA

[Andrew Halford]

Hi Listers,

I am running a partial RDA analysis and I have an environmental dataset
which includes a non-ordered factor representing reef type.

I want to test for a significant linear trend in the environmental dataset
as part of the process of testing for spatial autocorrelation.

e.g. lineartest <- anova(rda(env,latlong))

I have coded this Factor variable up as a group of dummy variables equal to
the number of different reef types to run the test but I am unsure if I
need to drop one of the dummy variables before running the linear test?

I will revert back to a single Factor variable when I run the RDA as told
in the vegan documentation?

My reading tells me that the call to RDA in Vegan will automatically deal
with creating dummy variables from a Factor variable presented in the model
but this is not the case

cheers

Andy


Andrew Halford Ph.D
Research Scientist (Kimberley Marine Parks)
Dept. Parks and Wildlife
Western Australia

Ph: +61 8 9219 9795
Mobile: +61 (0) 468 419 473

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