Summary of permutations, combinations and probability

Last updated: 24 Nov 2008

You should remember the following

Permutations

Permutations are where order does matter

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Combinations

Combinations are where order does not matter

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Basic rule of probability

When each possibility is equally likely.

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'And' probabilities

The probability of two independent outcomes both occurring can be found by multiplying their individual probabilities together.

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'Or' probabilities

The probability that either of two exclusive outcomes will occur can be found by adding their individual probabilities together.

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