Dear R-users,
I have the following problem. I have performed an experiment for which I
gathered a lot of data which I now want to test. The problem is that I
cannot find an appropriate test in R (I am a starter) and someone might give
me a hand. This is what I have done:
Across three sites (Site), I have laid out five transects (Trans)...meaning
five transects in each sites. In each transect I have five Microhabitats
(MH) which should be regarded as subplots (I think). In each transect, every
MH has the same position (so they are not randomized). I now want to test
the effect of Site and MH (nested in Trans) on my response variables.
This is what I do now: model<-aov(Response~Site*MH+error(Trans/MH))
I get the following output:
Error: Trans
Df Sum Sq Mean Sq
Site 1 0.030294 0.030294
Error: Trans:MH
Df Sum Sq Mean Sq
Site 1 10.8367 10.8367
MH 3 0.2836 0.0945
Error: Within
Df Sum Sq Mean Sq F value Pr(>F)
Site 2 0.92504 0.46252 11.7304 5.880e-05 ***
MH 4 1.86688 0.46672 11.8370 5.645e-07 ***
Site:MH 8 1.17041 0.14630 3.7105 0.001615 **
Residuals 54 2.12917 0.03943
---
Signif. codes: 0 ?***? 0.001 ?**? 0.01 ?*? 0.05 ?.? 0.1 ? ? 1
How do I read this?
Any help appreciated!
BTW: I also tried the lme function: model<-lme(Response~Site*MH,
random=~1|Trans/MH)
but then the output is really complicated.
-----
Dr. Bjorn JM Robroek
Ecology and Biodiversity Group
Institute of Environmental Biology, Utrecht University
Padualaan 8, 3584 CH Utrecht, The Netherlands
Email address: b.j.m.robroek at uu.nl
http://www.researcherid.com/rid/C-4379-2008
Tel: +31-(0)30-253 6091
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