2 messages · Chris Long, ONKELINX, Thierry
Hi, I'm looking to fit a family of quadratics in (x,y) with a random factor offset in one variable. The model would look like this: outcome ~ x^2 + x*(y+F) + (y+F)^2 + 1 with F a random factor. If this were linear in x,y it'd be no problem: outcome ~ x + y + 1|F. Is there a way to get either lme4 to estimate a model like this? If not, what's my best route?
Christopher D. Long, San Diego Padres, 100 Park Blvd, San Diego CA "Tick, clong, tick, clong, tick, clong, went the night." - Thurber
Dear Christopher, I think this can be done with a non-linear mixed model (nlmer in lme4). 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 Christopher D. Long Verzonden: zaterdag 3 maart 2012 11:42 Aan: r-sig-mixed-models at r-project.org Onderwerp: [R-sig-ME] Quadratic with Random Offset in One Dimension Hi, I'm looking to fit a family of quadratics in (x,y) with a random factor offset in one variable. The model would look like this: outcome ~ x^2 + x*(y+F) + (y+F)^2 + 1 with F a random factor. If this were linear in x,y it'd be no problem: outcome ~ x + y + 1|F. Is there a way to get either lme4 to estimate a model like this? If not, what's my best route? -- Christopher D. Long, San Diego Padres, 100 Park Blvd, San Diego CA "Tick, clong, tick, clong, tick, clong, went the night." - Thurber _______________________________________________ R-sig-mixed-models at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models