n<-1000 set.seed(2342) X<-rnorm(n,0,2) be.vec<-c(-0.5,1.0) eta<-cbind(rep(1,n),X) %*% be.vec pvec<-1/(1+exp(-eta)) Y<-rbinom(n,1,pvec) table(Y) log.like<-function(bev,Xv,Yv){ ev<-cbind(rep(1,length(Yv)),Xv) %*% bev pv<-1/(1+exp(-ev)) tvec<-sum(dbinom(Y,1,pv,log=T)) return(tvec) } log.like(be.vec,X,Y) be0<-be1<-seq(-1,3,by=0.1) lmat<-matrix(0,nrow=length(be0),ncol=length(be1)) for(i in 1:length(be0)){ for(j in 1:length(be1)){ lmat[i,j]<-log.like(c(be0[i],be1[j]),X,Y) } } image(be0,be1,lmat,col=heat.colors(50)) contour(be0,be1,lmat,nlevels=50,add=T) abline(v=be.vec[1],h=be.vec[2],col="red") image(be0,be1,lmat,col=heat.colors(50),xlab=expression(beta[0]),ylab=expression(beta[1])) contour(be0,be1,lmat,nlevels=50,add=T) abline(v=be.vec[1],h=be.vec[2],col="red")