Re: [R] HLM Model
Hi Silvano: Could you tell me what correlation=corSymm(form = ~ 1 |id) represents? In our case, team is random effect, trt, pairs, grade, school are fixed effect, and each team is within school. I still got the different results from both SAS and R. unstruct - gls(score~trt+pairs+grade+school, test,correlation=corSymm(form = ~ 1 |StudentID), + weights=varIdent(form=~1|team), method=REML) I tried school instead of StudentID, but I got error. unstruct - gls(score~trt+pairs+grade+school, test,correlation=corSymm(form = ~ 1 |school), + weights=varIdent(form=~1|team), method=REML) Error in vector(double, length) : vector size specified is too large Thanks for the help -- View this message in context: http://r.789695.n4.nabble.com/HLM-Model-tp3242999p3249518.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.
Re: [R] HLM Model
Hi Belle, try this: SAS: proc mixed data=test noclprint noinfo covtest noitprint method=reml; class pair grade team school; model score = trt pair grade school / solution ddfm=bw notest; random int / sub=team solution type=un r; run; R: require(nlme) unstruct - gls(score~trt+pair+grade+school, test, correlation=corSymm(form = ~ 1 |id), weights=varIdent(form = ~ 1|team), method=REML) summary(unstruct) -- Silvano Cesar da Costa Departamento de Estatística Universidade Estadual de Londrina Fone: 3371-4346 -- - Original Message - From: Belle ping...@gmail.com To: r-help@r-project.org Sent: Thursday, January 27, 2011 5:43 PM Subject: [R] HLM Model Hi I am trying to convert SAS codes to R, but some of the result are quite different from SAS. When I ran proc mixed, I have an option ddfm=bw followed by the model. How can I show this method in R (I am thinking that this maybe the reason that I can't get the similar results) below is my SAS codes: proc mixed data=test covtest empirical; class pair grade team school; model score = trt pair grade school/ solution covb ddfm=bw ; random int / sub=team solution type=un; run; I have tried both lmer and hglm, but non of them works. Could anyone tell me how can I covert this SAS codes to R? Thanks -- View this message in context: http://r.789695.n4.nabble.com/HLM-Model-tp3242999p3242999.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. __ 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.
Re: [R] HLM Model
I think it should be fm - lmer(score ~ trt + pair + grade + school + (1|team), test) The unstructured covariance matrix you use in proc mixed is not available in Rs function for mixed models -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Belle Sent: Thursday, January 27, 2011 2:44 PM To: r-help@r-project.org Subject: [R] HLM Model Hi I am trying to convert SAS codes to R, but some of the result are quite different from SAS. When I ran proc mixed, I have an option ddfm=bw followed by the model. How can I show this method in R (I am thinking that this maybe the reason that I can't get the similar results) below is my SAS codes: proc mixed data=test covtest empirical; class pair grade team school; model score = trt pair grade school/ solution covb ddfm=bw ; random int / sub=team solution type=un; run; I have tried both lmer and hglm, but non of them works. Could anyone tell me how can I covert this SAS codes to R? Thanks -- View this message in context: http://r.789695.n4.nabble.com/HLM-Model- tp3242999p3242999.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. __ 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.
Re: [R] HLM Model
Hi Harold: Yes, this was the R code that I tried, and got different result from SAS. Is that mean I cannot actually use R to run unstructured covariance matrix? How can I solve this problem if I need an unstructured covariance matrix method? Thanks for the help. -- View this message in context: http://r.789695.n4.nabble.com/HLM-Model-tp3242999p3243158.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.
Re: [R] HLM Model
Belle: Before I provide any more help, you'll need to follow some posting guide rules and describe what you have done with some R code, describe what the problem is, and describe what you are hoping to accomplish. The fact that the results you get from R and SAS are different doesn't mean there is a problem. If you can provide more details on what you are doing, what hasn't worked (specifically), then you will also find others on this list will provide help too. -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Belle Sent: Thursday, January 27, 2011 3:54 PM To: r-help@r-project.org Subject: Re: [R] HLM Model Hi Harold: Yes, this was the R code that I tried, and got different result from SAS. Is that mean I cannot actually use R to run unstructured covariance matrix? How can I solve this problem if I need an unstructured covariance matrix method? Thanks for the help. -- View this message in context: http://r.789695.n4.nabble.com/HLM-Model- tp3242999p3243158.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. __ 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.
Re: [R] HLM Model
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 SubjectEstimate Error Value Pr Z UN(1,1) team177.53 273.66 0.65 0.2583 Residual2161.15 67.1438 32.19 .0001 Solution for Fixed Effects Standard Effect pairsgrade schoolEstimate Error DFt ValuePr |t| Intercept 638.82 4.6127 5 138.49 .0001 trt -0.2955 3.4800 5 -0.08 0.9356 pairs 10.1899 7.1651 5 0.03 0.9799 pairs 231.1293 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 NameVariance Std.Dev. team (Intercept) 568.61 23.846 Residual 2161.21 46.489 Fixed effects: EstimateStd. Errort value (Intercept)540.402 43.029 12.559 trt 7.29113.0840.557 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.
Re: [R] HLM Model
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.
