library(MASS) plot(B.V,logL) abline(lm(logL~B.V),col="red",lty="dashed") abline(lqs(logL~B.V),col="blue",lty="dashed") newCol = c(rep("black",length(B.V)),"red") for(i in 1:100) { newPoint = locator(1) newX = c(B.V,newPoint$x) newY = c(logL,newPoint$y) plot(newX,newY,xlab="B.V",ylab="logL",col=newCol) abline(lm(logL~B.V),col="red",lty="dashed") abline(lqs(logL~B.V),col="blue",lty="dashed") abline(lm(newY~newX),col="red") abline(lqs(newY~newX),col="blue") }