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#1 2011-02-13 01:38:11

gAr
Member
Registered: 2011-01-09
Posts: 3,462

Probability, 2 fair coins

Hi all,

2 fair coins are flipped and atleast one of the outcomes is known to be a head., what is the probability that both outcomes are head?


"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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#2 2011-02-13 01:45:53

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 81,485

Re: Probability, 2 fair coins

Hi;

Looks good to me!

If you want to get confused about this go here.

http://trickofmind.com/?p=439


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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#3 2011-02-13 02:00:51

gAr
Member
Registered: 2011-01-09
Posts: 3,462

Re: Probability, 2 fair coins

Hi bobbym,

Thanks for looking into it, and thanks for the link!


"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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#4 2011-02-13 02:11:10

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 81,485

Re: Probability, 2 fair coins

Hi;

Just be careful some of those guys at that link are wrong.

Here is a pdf that you can download that covers the math and answers that question.

http://www.cse.buffalo.edu/~atri/course … lect4.pdf.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

Offline

#5 2011-02-13 02:25:03

gAr
Member
Registered: 2011-01-09
Posts: 3,462

Re: Probability, 2 fair coins

Hi,

yes, I verify before accepting any answer!
Thanks for this link too.


"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

Offline

#6 2011-02-13 23:54:46

Howardroark
Member
Registered: 2010-10-10
Posts: 382

Re: Probability, 2 fair coins

Hi gAr,

gAr wrote:

2 fair coins are flipped and atleast one of the outcomes is known to be a head., what is the probability that both outcomes are head?

You are right.. Here's a problem similar to yours..

A couple has 2 children. One of them is a girl. What is the probability that the other is a girl?


I come from a civilization which has given the world the number 0..

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#7 2011-02-14 02:59:10

gAr
Member
Registered: 2011-01-09
Posts: 3,462

Re: Probability, 2 fair coins

Hi Howardroark,

Thanks for looking into the problem.


"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

Offline

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