Generation of Random Samples and Permutations

In applications of statistical techniques as well as in Monte Carlo studies it is often necessary to take a random sample from a given finite set. A common form of random sampling is simple random sampling without replacement, in which a sample of n items is selected from a population N in such a way that every subset of size n from the universe of N items has an equal chance of being the sample chosen. This is equivalent to a selection mechanism in which n different items are selected, each with equal probability, n/N, and without regard to which other items are selected.