# R  CMD BATCH mc_asy.R mc_asy.out

postscript(file="xyplot_asy.eps",append=F,print.it=F)

make.data <- function( b, N, sseed=NULL) {
  if (!is.null(sseed)) set.seed(sseed)
  x  <- rnorm(N)
  e  <- rnorm(N,0,5)
  xb <- b[1] + b[2]* x
  y <- xb + e
  dta <- as.data.frame(cbind( y=y, x=x, e=e))
  return(dta)
}

## set some parameters

b <- c(1,3)

## number of cases in simulated data; choose values to put in here

Nvec <- c(n1, n2, n3, n4, n5, n6)

## set mfrow paramater to produce multiple plots on same page for 
## purposes of comparison

par(mfrow=c(3,2))

for(i in 1:nrow(as.matrix(Nvec))){

dta <- make.data( b, Nvec[i])
  Y <- dta$y
  X <- dta$x

xyreg<-lm(Y~X)

## plot the data points with limits on X and Y axes

plot(X,Y,xlim=c(-5,5),ylim=c(-12,12))

## add the true regression line to the plot

abline(b,lty=2)

## add the estimated regression line to the plot

abline(xyreg)

}