library(boot)
set.seed(101)
gal <- galaxies/1000

gal.boot <- boot(gal, function(x, i) median(x[i]), R = 1000)
gal.boot

boot.ci(gal.boot, conf = c(0.90, 0.95),
         type = c("norm","basic","perc","bca"))
plot(gal.boot)

sim.gen  <- function(data, mle) {
 n <- length(data)
 data[sample(n, replace = TRUE)]  + mle*rnorm(n)
}
gal.boot2 <- boot(gal, median, R = 1000,
 sim = "parametric", ran.gen = sim.gen, mle = 0.5)
boot.ci(gal.boot2, conf = c(0.90, 0.95),
         type = c("norm","basic","perc"))

attach(shoes)
t.test(B - A)
shoes.boot <- boot(B - A, function(x,i) mean(x[i]), R = 1000)
boot.ci(shoes.boot, type = c("norm", "basic", "perc", "bca"))
mean.fun <- function(d, i) {
 n <- length(i)
 c(mean(d[i]), (n-1)*var(d[i])/n^2)
}
shoes.boot2 <- boot(B - A, mean.fun, R = 1000)
boot.ci(shoes.boot2, type = "stud")
detach()

# End of ch05