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Probability

Average flips to see the first head

recursionfirst-step-analysisexpected-valuegeometric

You flip a fair coin repeatedly, stopping the moment it lands heads.

What is the expected number of flips, counting the flip that lands heads?

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First-Step Analysis: Conditioning on What Happens NextWaiting Time Until a Pattern AppearsThe ABRACADABRA ProblemThe Card-Pack Trading GameCatalan Numbers

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