[R] Repeated Measures/Linear Mixed Effects function
Andrew Robinson
A.Robinson at ms.unimelb.edu.au
Tue Oct 23 01:28:42 CEST 2007
Hi Keith,
it seems like a good starting position. I recommend that you spend
some time studying Pinheiro and Bates's book to see where t ogo from
here.
Cheers
Andrew
On Mon, Oct 22, 2007 at 02:58:51PM -0800, Keith Cox wrote:
> I have three columns of data, Xc, Trt and fish. This was a repeated
> measures design with 6 measurements taken from each of 5 fish. Xc is the
> actual measurement, Trt is the treatment, and fish is the fish number. Data
> can be seen below (hopefully it is in the column format). I would like to
> look for differences between treatments in a repeated measures format. I
> used the following code
>
>
>
> library(nlme)
>
>
>
> summary(lme(Xc~trt,data=R.exp,random=~1|fish))
>
>
>
> This seems to work and I would like to know if
>
>
>
> 1) this is the right function for my question, if so, then
>
> 2) in the summary, value is the first column, but what value is this. I
> have searched in vain and cannot find the answer. Any help or links to
> examples would be appreciated greatly.
>
> Fixed effects: Xc ~ trt
>
> Value Std.Error DF t-value p-value
>
> (Intercept) 103.62 2.619657 20 39.55480 0
>
> trtB -33.28 1.991197 20 -16.71356 0
>
> trtC -39.38 1.991197 20 -19.77705 0
>
> trtD -32.60 1.991197 20 -16.37206 0
>
> trtE -47.32 1.991197 20 -23.76460 0
>
> trtF -39.58 1.991197 20 -19.87749 0
>
>
>
>
> Xc
>
> Trt
>
> fish
>
>
> 109.1
>
> a
>
> 1
>
>
> 73
>
> b
>
> 1
>
>
> 68.4
>
> c
>
> 1
>
>
> 74.8
>
> d
>
> 1
>
>
> 60.3
>
> e
>
> 1
>
>
> 57
>
> f
>
> 1
>
>
> 106
>
> a
>
> 2
>
>
> 72.3
>
> b
>
> 2
>
>
> 67
>
> c
>
> 2
>
>
> 70.6
>
> d
>
> 2
>
>
> 58.2
>
> e
>
> 2
>
>
> 66.2
>
> f
>
> 2
>
>
> 102
>
> a
>
> 3
>
>
> 67.1
>
> b
>
> 3
>
>
> 61
>
> c
>
> 3
>
>
> 68.4
>
> d
>
> 3
>
>
> 50.2
>
> e
>
> 3
>
>
> 64.7
>
> f
>
> 3
>
>
> 105
>
> a
>
> 4
>
>
> 76.6
>
> b
>
> 4
>
>
> 68.8
>
> c
>
> 4
>
>
> 77.7
>
> d
>
> 4
>
>
> 61.8
>
> e
>
> 4
>
>
> 75.7
>
> f
>
> 4
>
>
> 96
>
> a
>
> 5
>
>
> 62.7
>
> b
>
> 5
>
>
> 56
>
> c
>
> 5
>
>
> 63.6
>
> d
>
> 5
>
>
> 51
>
> e
>
> 5
>
>
> 56.6
>
> f
>
> 5
>
>
>
>
>
>
>
>
>
>
>
>
>
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>
>
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>
>
> Marlin Keith Cox Ph.D.
>
> At-Sea Processor Professorship of Fisheries Biology
> Science Chair
>
> Sheldon Jackson College
>
> Sitka, Alaska 99835
>
> 907.747.5296
>
> http://www.sheldonjackson.edu
>
>
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
--
Andrew Robinson
Department of Mathematics and Statistics Tel: +61-3-8344-9763
University of Melbourne, VIC 3010 Australia Fax: +61-3-8344-4599
http://www.ms.unimelb.edu.au/~andrewpr
http://blogs.mbs.edu/fishing-in-the-bay/
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