\begin{Schunk}
\begin{Sinput}
 x <- 0:10
 y <- dpois(x, lambda = 1.3)
 par(mfcol = c(1, 2))
 plot(x, y, type = "h", lty = 4, xlab = expression(x ~ ~group("(", lambda == 
      1.3, ")")), ylab = "Probability")
 points(x, y, pch = 16)
 y <- dpois(x, lambda = 4)
 plot(x, y, type = "h", lty = 4, xlab = expression(x ~ ~group("(", lambda == 
      4, ")")), ylab = "Probability")
 points(x, y, pch = 16)
 par(mfcol = c(1, 1))
\end{Sinput}
\end{Schunk}
