Plotting confidence intervals to see which contain true mean.

plot_ci.r

# create a blank plot
plot(x=c(10,20),y=c(0,40), type="n")
abline(v=15,lty=2)


# plot line segments to represent confidence intervals
# add red lines for CI's that do not capture true mean of 15
# add dots for means
for(i in 1:40){
  x <- rnorm(30,15,2)
  res <- t.test(x,mu=15)
  if(res$conf.int[1]>15 | res$conf.int[2]<15){
    segments(x0=res$conf.int[1],y0=i,x1=res$conf.int[2],y1=i,col="red")
    points(x=res$estimate, y=i, pch=19, col="red")
  } else {
    segments(x0=res$conf.int[1],y0=i,x1=res$conf.int[2],y1=i)
    points(x=res$estimate, y=i, pch=19)
  }
}