

   RRaannddoomm SSaammpplleess aanndd PPeerrmmuuttaattiioonnss

        sample(x, size, replace=FALSE, prob)

   DDeessccrriippttiioonn::

        `sample' takes a sample of the specified size from the
        elements of `x' using either with or without replace-
        ment sampling according to the value of `replace'.

        By default `size' is equal to `length(x)' so that `sam-
        ple(x)' generates a random permutation of the elements
        of `x'.

        If `x' has length 1, sampling takes place from `1:x'.

        The optional `prob' agrument can be used to give a vec-
        tor of probabilities of obtaining the elements of the
        vector being sampled.

   EExxaammpplleess::

        x <- 1:12
        # a random permutation
        sample(x)
        # bootstrap sampling
        sample(x,replace=TRUE)

        # 100 Bernoulli trials
        sample(c(0,1), 100, replace = TRUE)

