Permutations, Ordered Counting, and the Multiplication Principle

Free SOA Exam P (Probability) lesson in General Probability. 20 min read, ~3,031 words.

Multiplication principle: if step 1 has outcomes and step 2 has, the pair has. Multiply across independent stages. Full permutation: order all distinct items in ways, with the convention. Partial permutation ( ): order of distinct items in ways. Order matters, no repeats. With repetition: fill ordered slots from options...