### Name: norm.ci
### Title: Normal Approximation Confidence Intervals
### Aliases: norm.ci
### Keywords: htest

### ** Examples

#  In Example 5.1 of Davison and Hinkley (1997), normal approximation 
#  confidence intervals are found for the air-conditioning data.
air.mean <- mean(aircondit$hours)
air.n <- nrow(aircondit)
air.v <- air.mean^2/air.n
norm.ci(t0=air.mean, var.t0=air.v)
exp(norm.ci(t0=log(air.mean), var.t0=1/air.n)[2:3])

# Now a more complicated example - the ratio estimate for the city data.
ratio <- function(d, w)
     sum(d$x * w)/sum(d$u *w)
city.v <- var.linear(empinf(data=city, statistic=ratio))
norm.ci(t0=ratio(city,rep(0.1,10)), var.t0=city.v)