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📖 Understanding Probability
Probability measures how likely an event is to occur. It is always between 0 (impossible) and 1 (certain). P(event) = Number of favourable outcomes / Total possible outcomes.
For complementary events: P(A) + P(A') = 1. So P(not A) = 1 − P(A).
For mutually exclusive events (can't both happen): P(A or B) = P(A) + P(B).
For independent events (one doesn't affect the other): P(A and B) = P(A) × P(B). Use tree diagrams to organise combined events.
🔑 Key Points to Remember
- ✓Probability: 0 ≤ P(A) ≤ 1
- ✓P(event) = favourable / total outcomes
- ✓P(not A) = 1 − P(A)
- ✓P(A or B) = P(A) + P(B) for mutually exclusive
- ✓P(A and B) = P(A) × P(B) for independent events
#probability#chance#events#high school#independent
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