Thank you very much. Is the following model would be corresponding to the data? Y_ijklt = m + a_l + b_k + c_j + d_t + (cd)_jt + u_ijklt Cheers, Samor
--- On Wed, 2/4/09, ONKELINX, Thierry <thierry.onkel...@inbo.be> wrote: From: ONKELINX, Thierry <thierry.onkel...@inbo.be> Subject: RE: [R] ANOVA in R To: samorgan...@yahoo.com, r-help@r-project.org Cc: r-sig-mixed-mod...@r-project.org Date: Wednesday, February 4, 2009, 3:21 PM Dear Samor, Note that the R-Sig-mixed-models is more suitable for that kind of questions. You need to add "+", ":" or "*" between the variables in the formula The correlation is lme() is not the same as the correlation in SAS. The correlation in lme() is the correlation among residuals, not among random effects. You need one of the pdClasses if you want to define the correlation among the random effects. Have a look at ?nlme::pdClasses Hence your code should probably look like this Model <- lme(response ~ seq + period + treat*time, random = pdCompSymm(form = ~1|SUB)) anova(Model) HTH, Thierry ---------------------------------------------------------------------------- ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, methodology and quality assurance Gaverstraat 4 9500 Geraardsbergen Belgium tel. + 32 54/436 185 thierry.onkel...@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-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] Namens Samor Gandhi Verzonden: woensdag 4 februari 2009 7:43 Aan: r-help@r-project.org Onderwerp: [R] ANOVA in R Hi,I'm using a repeated measures ANOVA in R using lme(). The SAS code would be: PROC MIXED DATA=[data set below]; CLASS pid treat period time seq; MODEL Y = seq period treat time treat*time; REPEATED time / SUBJECT=pid TYPE=cs; RUN, I donot have SAS, instead I have R and I would like to try the following: anova(lme(response ~ seq period treat time treat*time,random= ~1|SUB, correlation=corCompSymm())) Is this correct? Can I also write the model as Y_ijklt = m + a_l + b_k + c_j + d_t + (cd)_jt + u_ijkltY_ijklt is the response variable due to pid i, treat j, period k, seq l, and time t. Thank you very much in advance for your help :) Samor [[alternative HTML version deleted]] Dit bericht en eventuele bijlagen geven enkel de visie van de schrijver weer en binden het INBO onder geen enkel beding, zolang dit bericht niet bevestigd is door een geldig ondertekend document. The views expressed in this message and any annex are purely those of the writer and may not be regarded as stating an official position of INBO, as long as the message is not confirmed by a duly signed document. [[alternative HTML version deleted]]
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