### Name: envelope
### Title: Confidence Envelopes for Curves
### Aliases: envelope
### Keywords: dplot htest

### ** Examples

# Testing whether the final series of measurements of the gravity data
# may come from a normal distribution.  This is done in Examples 4.7 
# and 4.8 of Davison and Hinkley (1997).
grav1 <- gravity$g[gravity$series==8]
grav.z <- (grav1-mean(grav1))/sqrt(var(grav1))
grav.gen <- function(dat,mle)
     rnorm(length(dat))
grav.qqboot <- boot(grav.z,sort,R=999,sim="parametric",ran.gen=grav.gen)
grav.qq <- qqnorm(grav.z,plot=FALSE)
grav.qq <- lapply(grav.qq,sort)
plot(grav.qq,ylim=c(-3.5,3.5),ylab="Studentized Order Statistics",
     xlab="Normal Quantiles")
grav.env <- envelope(grav.qqboot,level=0.9)
lines(grav.qq$x,grav.env$point[1,],lty=4)
lines(grav.qq$x,grav.env$point[2,],lty=4)
lines(grav.qq$x,grav.env$overall[1,],lty=1)
lines(grav.qq$x,grav.env$overall[2,],lty=1)