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I was wondering, if you flip a fair coin $5$ times, whether you can calculate the probability of getting at least one head is calculated like this:

You can do the complement of getting at least one head which is TTTTT: $\dfrac1{2^5} =\dfrac1{32}$

Then you do $$1-\frac1{32}= \frac{31}{32}\;,$$ so that's the possibility of getting at least one head after a flip?


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up vote 5 down vote accepted

Yes, that's correct. This technique is often called complementary counting.

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