Hi all I use the function "simtest" for execute a Dunnett's test See: y<-c(6.5,1.60E+01,1.05E+01,6.7,1.78E+01,6.6,4.7,7.5,1.63E+01,4.2,1.15E+01,2. 79E+01,9,1.07E+01,3.00E+01,9.5,1.42E+01,1.40E+01,9.4,6.1,3.00E+01,8.4,3.00E+ 01,3.00E+01,1.32E+01,3.00E+01,1.58E+01,3.00E+01,1.73E+01,1.51E+01,1.01E+01,6 .1,8,3.00E+01,2.20E+01,6.5,9,3.00E+01,1.36E+01,1.67E+01) f1<- factor(c(rep("A", 10),rep("B", 10),rep("C", 10),rep("D", 10))) m<-matrix(0,3,4) m[1,1]<-1 m[2,2]<-1 m[3,4]<-1 m[1,3]<--1 m[2,3]<--1 m[3,3]<--1 result<-summary(simtest(y ~ f1,type="Dunnett",cmatrix=cbind(0,m))) I retrieve result$p.value.adj as an array but how to know which groups are compared by row Because it seem that the array is ordered by result$estimate Thanks Laurent Houdusse Analyste Programmeur