Some basic concepts from combinatorial analysis are often used in statistics and probability theory. Follow the links for details on each concept.
Permutations - how to order a set of objects; how to count the number of possible ways to order them, using the factorial function. Learn how to answer questions such as: how many four-letter words can be formed with the letters a, c, e, t?
k-permutations - how to select a subset of objects and order them; in how many different ways this can be done. For example: how many five-letter words can be formed using the standard alphabet?
Combinations - how to pick some objects from a larger group; how to enumerate the possible ways to do so, using binomial coefficients. E.g.: how many different ways are there to select four students from a class of thirty?
Partitions - how to subdivide groups of objects into subgroups; how to count how many possible subdivisions there are. For instance, how many ways are there to form two five-player teams from a group of ten people?