# File "Rjack2".

numreps = 100

n = 100

estlist = jacklist = NULL

for (rep in 1:numreps) {

    # Generate some data.
    x = runif(n)

    estimate = median(x)

    # Compute the jackknife estimate of variance.
    thetam = rep(0,n)
    for (i in 1:n) {
	if (i==1)
	    xm = x[2:n]
	else if (i==n)
	    xm = x[1:(n-1)]
	else
	    xm = c(x[1:(i-1)], x[(i+1):n])
        thetam[i] = median(xm)
    }

    thetadot = mean(thetam)

    jackvarest = (n-1)/n * sum((thetam - thetadot)^2)

    jacklist = c(jacklist, jackvarest)
    estlist = c(estlist, estimate)

}

truevarest = var(estlist)

print(jacklist)
print(mean(jacklist))
print(truevarest)