## Permutations

In Chapter 7, we focused on using statistics to calculate probabilities. Using relative frequencies, we were able to calculate the likelihood of events using the history of what has happened in the past. However, in some applications we are interested in counting arrangements of objects in order to calculate the likelihood of a particular arrangement, For instance, suppose we wish to rank applicants for a job from a larger pool. How likely is it that the top five applicants are female? To answer this question, we need to be able to count the number of ways to rank five applicants from a larger pool. This will require us to learn about permutations. Permutations are used to calculate arrangements of objects where each objects are chosen without repetition.

**Read **in Section 8.1

- How do you count choices using the Multiplication Principle?
- What is factorial notation?
- What is a permutation?

**Watch **Video