conditional probability

条件概率

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Translation evidence: Literature usage

Meaning in context

For events A,BA,B with P(B)>0P(B)>0, the probability of AA given BB is P(A∣B)=P(A∩B)/P(B)P(A\mid B)=P(A\cap B)/P(B).

当条件事件B的概率为正时，A在B条件下的概率等于交事件的概率除以B的概率。

Example

For a fair die, P({6}∣{2,4,6})=1/3P(\{6\}\mid\{2,4,6\})=1/3.

Usage and distinctions

The elementary ratio does not define conditioning on a probability-zero event.

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Definition sources

  1. Richard Weber — Probability§6.1 Conditional probability · Checked 2026-10-14

Translation sources

  1. 上海交通大学 — 概率统计，第1章第1章，核心概念与定义：条件概率（定义 #D） · Checked 2026-10-14
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