\begin{Schunk}
\begin{Sinput}
 plot(y ~ (as.numeric(xcat2)-1), xlab = "One Mysterious Predictor", ylab="An Output Variable", xaxt = "n")
 axis(1, at = 1:5, labels = c("R=0", "M=1", "D=2", "A=3", "F=4"))
 m1 <- lm(y ~ as.numeric(xcat2)-1)
 abline(m1, lwd = 2)
 legend("topright", legend=c("OLS Predicted value"), lty = 1)
\end{Sinput}
\end{Schunk}
