\begin{Schunk}
\begin{Sinput}
 par(xpd=T)
 mh <- hist(dat$sei, xlab= "Socio-economic Index", ylab = "Proportion", xlim=c(0,100), ylim = c(0, 0.04), breaks=25, prob=T, main="")
 densei <- density(dat$sei, na.rm=T)
 lines(densei, lty=2)
 text(10, 0.01, label=c("kernel \n density \n estimate"),pos=3)
 arrows(10, 0.01, 18,0.003, lty=2, length=0.1)
 text( 0.8*max(dat$sei,na.rm=T), max(densei$y), label = paste("mean=", round(mean(dat$sei, na.rm =T),2), "\n std.dev. =", round(sd(dat$sei,na.rm=T),2)), pos=3 )
\end{Sinput}
\end{Schunk}
