ps.options(horizontal=FALSE,onefile=FALSE)
ps.options(pagecentre=TRUE)
ps.options(paper="letter")
ps.options(width=7.0,height=6.0)

lev  <- matrix(scan("11f1f1f0s1440010.lev"),ncol=4,byrow=T)

par(mfrow=c(1,1))

postscript(file="lev.eps")

plot(c(lev[,1],lev[,1]),c(lev[,2],lev[,4]),
   main="Conditional Variance Function of S&P Returns, Log Volume",
   xlab="Percentage Growth",ylab="Variance", type="n")
   lines(lev[,1],lev[,2],type="l",lty=1)
   lines(lev[,1],lev[,4],type="l",lty=2)
dev.off()