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October 6th, 2013, 01:02 PM   #1
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Probability of getting an even number of tails for x throws?

Need help with the formula to calculate the probability for getting an even amount of tails after (0,1,2,...,491) coin flips. would be very thankfull for some help
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October 6th, 2013, 03:09 PM   #2
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Re: Probability of getting an even number of tails for x thr

If zero is considered even, the probability of getting an even number of tails on zero coin tosses is 1 and the probability of getting an even number of tails on every other number of tosses is 1/2.
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October 6th, 2013, 03:17 PM   #3
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Re: Probability of getting an even number of tails for x thr

well i know the probabilityis 1/2 but i think i need to do an binomial of it because i need to figure out the probability of getting a even number of tails in say 491 coin flips
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October 6th, 2013, 03:19 PM   #4
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Re: Probability of getting an even number of tails for x thr

only well motivated answers are accepted
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October 6th, 2013, 04:06 PM   #5
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Re: Probability of getting an even number of tails for x thr

There are 2^n possible outcomes, 2^(n - 1) of which have an even number of tails. 2^(n - 1)/2^n = 1/2.
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October 6th, 2013, 04:56 PM   #6
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Re: Probability of getting an even number of tails for x thr

You could use mathematical induction on the number of tosses if you want a formal proof.
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October 6th, 2013, 05:23 PM   #7
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Re: Probability of getting an even number of tails for x thr

Quote:
Originally Posted by Kuroniirp
only well motivated answers are accepted
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