I'm working through some problems in a beginners programming book. The author mentions a formula for calculating the number of ways of picking out n things from a collection of m of them:
But he does not give a name for the formula. Does anyone happen to know what it is called? I need to do some related research.

I think this is related to permutation and combination of math. Refer to this link: http://www.mathsisfun.com/combinator...mutations.html
I hope it helps Good luck mate.

"Permutations"?

"Probability" (of n results over m tries)?

Check out these two links:

http://www.visioniasonline.com/templ...mbinations.pdf

http://boards.straightdope.com/sdmb/.../t-558067.html

'Hope that helps .. PSM

The function you provide is for combinations. The name of the function (or formula as you call it) is the binomial coefficient. Us statisticians would say "m choose n" when we run across it in our daily lives. It is not a probability, but is the number of n combinations we can make from a set of m items.

For example, given the set {1, 2, 3} (i.e., m = 3), we can make three sets of 2 (i.e., n = 2). The combinations of two are {1, 2}, {1, 3}, and {2, 3}.

This is different from permutations which are all the ways m items can be arranged. Given the same set {1, 2, 3}, there are six permutations (or ways to order those number). These six are {1, 2, 3}, {1, 3, 2}, {2, 1, 3}, {2, 3, 1}, {3, 1, 2}, and {3, 2, 1}.

Get it?

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