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Probability That Depends on Context
Probability That Depends on Context
What's the chance of rain if it's cloudy? What's the probability a student passes an exam if they've been attending classes regularly? These situations involve conditional probability - where the likelihood of one event depends on whether another event has already occurred.
Conditional probability helps us make better predictions by considering additional information.
What is conditional probability?: The probability of one event occurring given that another event has already occurred. It restricts the sample space to only the outcomes where the condition is met.
Mathematics glossary
- What is conditional probability?
- The probability of one event occurring given that another event has already occurred. It restricts the sample space to only the outcomes where the condition is met.
- What does the vertical bar | mean in P(A|B)?
- It means 'given that'. P(A|B) is read as 'the probability of A given B'. The event after the bar is the condition — it is already known to have occurred.
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Exam Tips
- Identify the condition - what's given (after the |)
- Reduce your focus - only consider outcomes where the condition is true
- Use tables and diagrams - they make conditional probability clearer
- Check your answer - conditional probabilities should still be between 0 and 1
- Practice with real contexts - medical tests, weather, games
Now try it yourself
Quiz · Question 1 of 14
What does the notation P(A|B) mean?
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