Re: [R-sig-eco] Predict with 2 factors in an additive model
On Fri, 2011-10-14 at 17:09 -0600, Manuel Spínola wrote: Dear list members, I have an additive linear model (see below fro a reproducible example) and I want to use the function predict to have the value of the response variable for each level of factor f1 and each level of factor f2 in the additive model (not interaction). When I did predict I only get 2 values. Because there are only two rows in `newdata`! If you want f1-a with f2-a and f1-a with f2-b, and f1-b with f2-a and f1-b with f2-b, that necessitates four rows in `newdata` to contain the combinations. G y=rnorm(40,1,1) f1=c(rep(a,20),rep(b,20)) f2=c(rep(a,10),rep(b,10),rep(a,10),rep(b,10)) data=data.frame(y,f1,f2) mod1 = lm(y ~ f1 + f2, data=data) summary(mod1) newData = data.frame(f1 = factor(c(a, b)), f2 = factor(c(b, a))) predict(mod1, newdata = newData, appendData = TRUE) 1 2 1.0460148 0.9468983 Thank you very much in advance. Best, Manuel ___ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology -- %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% Dr. Gavin Simpson [t] +44 (0)20 7679 0522 ECRC, UCL Geography, [f] +44 (0)20 7679 0565 Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/ UK. WC1E 6BT. [w] http://www.freshwaters.org.uk %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% ___ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
[R-sig-eco] Predict with 2 factors in an additive model
Dear list members, I have an additive linear model (see below fro a reproducible example) and I want to use the function predict to have the value of the response variable for each level of factor f1 and each level of factor f2 in the additive model (not interaction). When I did predict I only get 2 values. y=rnorm(40,1,1) f1=c(rep(a,20),rep(b,20)) f2=c(rep(a,10),rep(b,10),rep(a,10),rep(b,10)) data=data.frame(y,f1,f2) mod1 = lm(y ~ f1 + f2, data=data) summary(mod1) newData = data.frame(f1 = factor(c(a, b)), f2 = factor(c(b, a))) predict(mod1, newdata = newData, appendData = TRUE) 1 2 1.0460148 0.9468983 Thank you very much in advance. Best, Manuel -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.ac.cr mspinol...@gmail.com Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de río https://sites.google.com/site/lobitoderio/ Institutional website: ICOMVIS http://www.icomvis.una.ac.cr/ [[alternative HTML version deleted]] ___ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
Re: [R-sig-eco] Predict with 2 factors in an additive model
Try this newData = data.frame(f1 = factor(c(a,a,b,b)), f2 = factor(c(b, a,b,a))) And use that newData in your predict statement On Oct 14, 2011, at 4:09 PM, Manuel SpÃnola mspinol...@gmail.com wrote: newData = data.frame(f1 = factor(c(a, b)), f2 = factor(c(b, a))) [[alternative HTML version deleted]] ___ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
