\begin{Schunk}
\begin{Sinput}
 xvals <- seq(0,10,length.out=1000)
 gam1 <- dgamma(xvals, shape=2, scale=1/2)
 gam2 <- dgamma(xvals, shape=10, scale= 1/10)
 gam3 <- dgamma(xvals, shape=50, scale= 1/50)
 plot(xvals, gam1, type="l", xlab="x",ylab="Gamma probability density",  ylim=c(0,2))
 lines(xvals, gam2, lty=2)
 lines(xvals, gam3, lty=3)
 legend("topright", legend=c("alpha=2","alpha=10","alpha=50"),lty=c(1,2,3))
\end{Sinput}
\end{Schunk}
