The empirical statement on the proc mixed line gives you robust standard errors, I don't think you get them in R.
In SAS you specify that the predictors are to be dummy coded using the class . Are they factors in R? I can't tell from the SAS output, because the formatting has been lost. However, it appears that in R you did not dummy code them. It also appears you haven't given use all of the SAS output. Jeremy On 27 January 2011 15:52, Belle <ping...@gmail.com> wrote: > > Hi Harold: > > I know the outputs are different between SAS and R, but the results that I > got have big difference. > > Here is part of the result based on the SAS code I provided earlier: > > Cov Parm Subject Estimate Error > Value Pr > Z > > UN(1,1) team 177.53 273.66 > 0.65 0.2583 > Residual 2161.15 > 67.1438 32.19 <.0001 > > Solution for Fixed > Effects > > > Standard > Effect pairs grade school Estimate Error > DF t Value Pr > |t| > > Intercept 638.82 4.6127 > 5 138.49 <.0001 > trt -0.2955 > 3.4800 5 -0.08 0.9356 > pairs 1 0.1899 7.1651 > 5 0.03 0.9799 > pairs 2 31.1293 6.0636 > 5 5.13 0.0037 > . > . > . > > In R: > library(lme4) > mixed<- lmer(Pre~trt+pairs+grade+school+(1|team), test) > > result: > > Random effects: > Groups Name Variance Std.Dev. > team (Intercept) 568.61 23.846 > Residual 2161.21 46.489 > > Fixed effects: > Estimate Std. Error t value > (Intercept) 540.402 43.029 12.559 > trt 7.291 13.084 0.557 > pairs -3.535 6.150 -0.575 > > In random effect, the variance of team in SAS is 177.53, but it is 568.61 in > R. Also I have negative estimate for trt in SAS but positive estimate for > trt in R. I am wondering how this happened, and how can I solve this problem > so that I can get similar result from both software. > > Also does R provides result for fixed effect of each level? For example, the > result of pair1, pair2,pair3,..., and grade1, grade2, grade3,... > > -- > View this message in context: > http://r.789695.n4.nabble.com/HLM-Model-tp3242999p3243475.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > -- Jeremy Miles Psychology Research Methods Wiki: www.researchmethodsinpsychology.com ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
