Dear Thiery Thanks for your email. The subscripts i and j are the subject i and j (in our case the subjects are the lizards (players)). U is the n vector of the random effects (U1,...,Un). Each random effect Ui is supposed to be distributed as normal with mean 0 and variance sigma^2. For our data (attached in Data.txt file), the matrix is of order (77*77), and contains only 100 non missing data (all the remaining are missing (NA)). The matrix of covariates (attached in Covariates.txt) is of order (77*4). We would like to estimate the four fixed effects parameters associated to the covariate matrix and the variance of the random effects Ui. Best regards Dr Feddag
On 07/03/2012 10:36, ONKELINX, Thierry wrote:
We need more information to connect your data to the model. What is the interpretation of the subscript i and j and U in connection to your data? How does your dataset look like? Best regards, Thierry 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 at 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 at r-project.org [mailto:r-sig-mixed-models-bounces at r-project.org] Namens Feddag Mohand-Larbi Verzonden: dinsdag 6 maart 2012 17:18 Aan: r-sig-mixed-models at r-project.org Onderwerp: [R-sig-ME] Question on the glmer function of the lme4 R package Dear all, Could you please help me in the estimation of the different parameters of the Bradley-Terry model with random effects by the glmer function of the lme4 R package. The model, the marginal likelihood and the real data and the main question are described in the attached file. Best regards Dr Feddag
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