search for: fixed_effect

Displaying 2 results from an estimated 2 matches for "fixed_effect".

2012 Nov 07
2
LMER vs PROC MIXED estimates
...SAS code is as follows (trying to randomise X2 and Intercept): PROC MIXED DATA = <DATASET NAME> NAMELEN=100 METHOD=REML MAXITER=1000; CLASS GEOGRAPHY; MODEL y = X1 X2 X3/SOLUTION; RANDOM INTERCEPT X2/SOLUTION SUBJECT = GEOGRAPHY; ODS OUTPUT SOLUTIONR=RANDOM_EFFECT; ODS OUTPUT SOLUTIONF= FIXED_EFFECT; RUN; the equivalent code that I was writting in R is as follows: testdata <- read.csv("adstest.csv",header=TRUE,sep=",") attach(testdata) library(lme4) options(contrasts = c(factor = "contr.SAS",ordered = "contr.poly")) lmm.2=lmer(y~X1+X2+X3 + (X2...
2011 Aug 08
1
mixed model fitting between R and SAS
Hi al, I have a dataset (see attached), which basically involves 4 treatments for a chemotherapy drug. Samples were taken from 2 biopsy locations, and biopsy were taken at 2 time points. So each subject has 4 data points (from 2 biopsy locations and 2 time points). The objective is to study treatment difference.? I used lme to fit a mixed model that uses "biopsy.site nested within pid"