[R-sig-ME] lmer, formula composition, repeated measurement

[ONKELINX, Thierry]

Have a look at http://glmm.wikidot.com/faq and look for "Model specification"

Best regards,

ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
Kliniekstraat 25
1070 Anderlecht
Belgium
+ 32 2 525 02 51
+ 32 54 43 61 85
Thierry.Onkelinx op inbo.be
www.inbo.be

To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of.
~ Sir Ronald Aylmer Fisher

The plural of anecdote is not data.
~ Roger Brinner

The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data.
~ John Tukey


-----Oorspronkelijk bericht-----
Van: r-sig-mixed-models-bounces op r-project.org [mailto:r-sig-mixed-models-bounces op r-project.org] Namens rad ushan
Verzonden: woensdag 9 mei 2012 9:00
Aan: r-sig-mixed-models op r-project.org
Onderwerp: [R-sig-ME] lmer, formula composition, repeated measurement

Dear all, I have a simple question regarding how to compose a formula for using with lmer.
Say I have 10 subjects with different phenotypes (dependent var Y) and one predictor variable measured 3 times for each subject (X). By other words:

Y Subj X
1  1  1.2
1  1  1.3
1  1  0.7
3  2  2.1
3  2  2.5
3  2  4
5  3  3
5  3  4
5  3  4
...

I would like know the correlation of Y with X (Y~X) and the effect of within subject variance on this correlation (say correlation corrected adjusted with variance).
How to compose a formula for lmer function? Is it correct: Y~X|subj or may be Y~x+1|subj? Thank you.

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