Re: [R] Nested design

From: Dennis Murphy <djmuser_at_gmail.com>
Date: Sat, 28 May 2011 06:49:21 -0700

Hi:

Essentially, you are asking for free statistical advice, which is not within the intended scope of R-help. It's always better to consult with someone locally, and as luck would have it, your university apparently provides free statistical consulting for faculty and grad students:

http://www.uu.nl/faculty/socialsciences/EN/organisation/Departments/methodologystatistics/consultation/Pages/default.aspx

I would suggest that you contact someone there and have a face-to-face discussion rather than a possibly extended back-and-forth on the Net.

Dennis

On Sat, May 28, 2011 at 6:09 AM, unpeatable <bjorn.robroek_at_gmail.com> wrote:
> 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
> --
> View this message in context: http://r.789695.n4.nabble.com/Nested-design-tp3557404p3557404.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help_at_r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



R-help_at_r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sat 28 May 2011 - 13:53:10 GMT

This quarter's messages: by month, or sorted: [ by date ] [ by thread ] [ by subject ] [ by author ]

All messages

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Sat 28 May 2011 - 14:10:11 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.

list of date sections of archive