Basic relationships in probability

• Mutually exclusive events
• Non-mutually exclusive events
• Independent events
• Dependent events

If events A and B are mutually exclusive then: {{{ P(A or B) = P(A) + P(B) }}}

If events A and B are non mutually exclusive then: {{{ P(A or B) = P(A) + P(B) - P(A and B) }}}

If events A and B are independent then: {{{ P(A and B) = P(A) X P(B) }}}

If events A and B are dependent then:

A)

Where P(B | A) is the probability that B occurs given that A already happened.

Part of M7-Quantitative Decision Methods-S2 - Probability and decision trees