ACT Preparation / Unit 15 ACT 1422 short lesson, about 20 seconds
Independent Events
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The idea
Events are independent when one does not change the probability of the other. Then P(A and B) = P(A) × P(B).
In practice
Two coin flips both landing heads: 1/2 × 1/2 = 1/4. Rolling a 6 and flipping heads: 1/6 × 1/2 = 1/12.
Where people slip
Drawing without replacement breaks independence: the second draw's probabilities change.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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