Formula Review
9.1 Terminology
A and B are events
P(S) = 1 where S is the sample space
0 ≤ P(A) ≤ 1
P(A|B) = [latex]\frac{\text{P(A AND B)}}{\text{P(B)}}[/latex]
9.2 Independent and Mutually Exclusive Events
If A and B are independent, P(A AND B) = P(A)P(B), P(A|B) = P(A) and P(B|A) = P(B).
If A and B are mutually exclusive, P(A OR B) = P(A) + P(B) and P(A AND B) = 0.
9.3 Two Basic Rules of Probability
The multiplication rule: P(A AND B) = P(A|B)P(B)
The addition rule: P(A OR B) = P(A) + P(B) – P(A AND B)
Attribution
By Barbara Illowsky and Susan Dean, Introductory Statistics, Access for free at https://openstax.org/books/introductory-statistics/pages/1-introduction. Jun 23, 2022 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License CC BY-NC-SA 4.0. The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.
