Basic probability

Math

Definition

The measure of how likely an event is to occur, expressed as a number from 0 (impossible) to 1 (certain). The probability of an event equals the number of favorable outcomes divided by the total number of equally likely outcomes.

Examples

  • The probability of rolling a 3 on a fair die is 1/6
  • The probability of drawing a red card from a standard deck is 26/52 = 1/2
Key Fact

P(event) = favorable outcomes / total outcomes; 0 ≤ P ≤ 1

Related Terms

Probability rules Permutations and combinations Binomial probability Conditional statements

Study This Concept

Practice basic probability with free review games in these units:

Algebra 1 Unit 10: Data Analysis and Probability