# Generates n observations from the tail of a standard normal distribution 
# by using the accept-reject method with a truncated Weibull distribution.
# Outputs the sample and two graphs.  A normal QQ plot is produced by default,
# though of course the sample is non-normal. You may want to be sure to 
# assign the function to a variable, or the entire
# sample will be printed on screen (you'll still get your graphs though).
tailnorm=function(n,pl=T){
x1=NULL
while(length(x1)<n){
u=runif(1)
v=runif(1)
x=sqrt(9-2*log(v))
x1=c(x1,x[(x*u<=3)])
}
if (pl==T){
win.graph()
par(mfrow=c(2,1))
qqnorm(x1)
qqline(x1)
hist(x1,breaks=seq(3,max(x1)+.1,by=.1))
}
x1
}