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2017 Aug 11
0
PROC MIXED RANDOM equivalence in R nlme
Dear Dennis, Your question assumes that people know both SAS PROC MIXED and R nlme. Only a limited number of people do. Add the mathematical formulation of the model. That will increase the number of people that can help you. Adding the number of levels in each categorical variable and the number of observation per group is useful too. Best regards, ir. Thierry Onkelinx Instituut voor natuur-
2009 Feb 26
4
Singularity in a regression?
R friends, In a matrix of 1s and 0s, I'm getting a singularity error. Any helpful ideas? lm(formula = activity ~ metaF + metaCl + metaBr + metaI + metaMe + paraF + paraCl + paraBr + paraI + paraMe) Residuals: Min 1Q Median 3Q Max -4.573e-01 -7.884e-02 3.469e-17 6.616e-02 2.427e-01 Coefficients: (1 not defined because of singularities)
2017 Aug 10
4
PROC MIXED RANDOM equivalence in R nlme
I am trying to reproduce some old SAS PROC MIXED code using R and nlme. The data consists of emission readings from vehicles and fuel properties. All variables are real numbers except "study" and "vehicle", which are character. Unfortunately, since the data are confidential, I'm unable to provide an example. The original SAS v6.12 code is provided below: