Math

• Experiment - in any given situation results are called outcomes.
• Event - a desired outcome
• Sample space - refers to the set of all possible outcomes
• Factorial - The result of multiplying a sequence of descending natural numbers from n to 1.
• Permutation - refers to all possible arrangements of a collection of things where the order is important
• P (n,r) = n!
• The number of permutations of n distinct objects taken r at a time is given by: n!/(n-r)!
• The number of permutations of n distinct objects of which n1 are similar, n2 are similar, ..., nk are similar is given by: n!/n1!,n2!, ..., nk!
• The number of permutations of n objects arranged in a circle is given by: (n-1)!
• The number of permutations of n objects in a key ring and is given by: (n-1)!/2
• Combination - refers to all possible arrangements in which the order of the objects is not important or taken into consideration
• C = n!/ r! (n-r)!