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A conditional probability differs from an ordinary one because the count is divided by:
AThe whole sample space
BThe number of trials
CThe outcomes in the condition
DThe outcomes in the event
Answer & Solution
Correct answer: C. The outcomes in the condition
1. Conditioning on B means treating B as the new universe of possibilities.
2. The conditional probability of A given B is written P(A given B).
3. Then we divide that by the number of outcomes B, rather than by the sample space.
4. That is why conditioning can raise or lower a probability sharply.
5. Using the whole sample space instead would give the unconditional probability.
_Source: OpenStax Introductory Statistics 2e (CC BY 4.0), Ch 3 'Probability Topics', sections 3.1-3.5_
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