# Counting, permutations, and combinations

This course is a part of Statistics and probability, a 16-course Topic series from Khan Academy.

This unit covers methods for counting how many possible outcomes there are in various situations. We'll learn about factorial, permutations, and combinations. We'll also look at how to use these ideas to find probabilities.

This course contains 4 segments:

Counting principle and factorial

The counting principal tells us that we can multiply the number of choices together to get a count of the total possible outcomes. If you own two pairs of pants and three shirts, then you have six possible outfits.

Permutations

Permutations count how many ways you can select and arrange items or people from a larger group. For example, how many different ways can we award a gold, silver, and bronze medal to three runners out of a group of 10?

Combinations

Combinations are similar to permutations. Combinations count how many ways we can pick a group of people or things from a larger group where order doesn't matter. For example, how many different groups of 3 people can a company with 10 employees send on a business trip?

Combinatorics and probability

Once we understand the counting principle, permutations, and combinations, we can use those concepts to calculate some pretty advanced probabilities!

Rating Not enough ratings 4 segments On Demand (Start anytime) Free Khan Academy On all desktop and mobile devices English Mathematics Data Science Math Statistics and probability

## Careers

An overview of related careers and their average salaries in the US. Bars indicate income percentile.

Behavioral Health Care Advocate Possible Telecommute \$36k

Coordinator, Cardiac Outcomes Department \$52k

Program Manager Clinical Outcomes Manager \$61k

Clinical Outcomes Quality Specialist \$66k

Program Manager Clinical Outcomes \$86k

Outcomes Specialist Manager \$94k

Outcomes Liaison Consultant \$99k

Project Manager, Clinical Outcomes \$106k

Value Analysis and Surgical Outcomes Program Manager \$111k

Outcomes Research \$117k

Coordinator, OR Study Program - Global Outcomes Research \$125k

Clinical Informatics Analyst, Outcomes Research & Analysis Manager \$126k

## Write a review

Your opinion matters. Tell us what you think.