Probability Sum Rule

Probability Sum Rule

PR-03
ASPCSPFoundational

Formula
Pf = 1 − Ps
When to Use

In a binary system, the probabilities of failure and success must sum to one.

Symbol Legend
SymbolMeaningUnitNote
PfProbability of failuredecimal
PsProbability of successreliabilityPs + Pf = 1.0

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