i try to generate 27*5 matrix of observation using the following code but is given error kindly assist and correct the problem x1<-c(-1,0,1,-1,0,1,-1,0,1,-1,0,1,-1,0,1,-1,0,1,-1,0,1,-1,0,1,-1,0,1) x2<-c(-1,-1,-1,0,0,0,1,1,1,-1,-1,-1,0,0,0,1,1,1,-1,-1,-1,0,0,0,1,1,1) x3<-c(-1,-1,-1,-1,-1,-1,-1,-1,-1,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1) mu<-50+5*(x1^2+x2^2+x3^2) sig<-100+5*((x1-0.5)^2+x2^2+x3^2) x.matrix<-matrix(0,nrow=27,ncol=5) for(i in 1:27){ x.matrix[i,j]<-rnorm(5,mu[i],sig[i]) } Thanks Ishaq [[alternative HTML version deleted]]