\begin{Schunk}
\begin{Sinput}
  xseq <- seq(0,10)
  xdpois <- dpois(xseq,lambda=3)
  plot(xdpois ~ xseq, type = "h", xlab = "a Poisson variate with lambda=3", ylab = "Probability", ylim = c(0, 1.2*max(xdpois)) )
  points(xseq, xdpois)
\end{Sinput}
\end{Schunk}
