Probability & Combinatorics
Basic

Complement Rule

Probability that an event does not occur.

Formula

P(A′)=1−P(A)P(A') = 1 - P(A)

Variables

AEvent

Example

P(not 6) = 1 - 1/6 = 5/6

Did You Know?

Often easier to compute the complement than the event directly.

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