Probability Map

1. Fundamental Counting Rule

1.1. m*n

1.2. Number of ways multiple events can occur.

2. Factorial Rule

2.1. n!

2.2. Number of different permutations.

3. Permutations rule (when all items are different)

3.1. n!/(n-r)!

3.2. Number of permutations when a certain number of items (n) are available, but only a few of them (r) are selected without replacement.

4. Permutations rule (when some items are identical)

4.1. n!/n1!n2!.....nk!

4.2. Number of permutations when a certain number is available, but only a few are used without replacement and some of the items are the same.

5. Combinations rule

5.1. n!/(n-r)!r!

5.2. Number of different combinations when a certain number is available, but only a few are used without replacement. *Order does not matter*