Math Is Fun Forum
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#51 2014-10-05 08:15:07
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Bayes' theorem problem
Have they changed it yet?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#52 2014-10-05 19:18:53
- Bob
- Administrator
- Registered: 2010-06-20
- Posts: 10,643
Re: Bayes' theorem problem
hi Agnishom,
This solution assumes that P(A) = P(B) = P(C) = P(D) = 1/4.
There's nothing in the wording of the problem that allows these assumptions. For all we know, there might only be 2 whites, in which case P(D) = 1 and the rest are zero.
Bob
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob 
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#53 2014-10-05 19:27:52
Re: Bayes' theorem problem
Thanks
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#54 2014-10-05 19:38:44
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Bayes' theorem problem
Did they change it yet?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#55 2014-10-06 05:39:07
Re: Bayes' theorem problem
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#56 2014-10-06 05:42:49
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Bayes' theorem problem
I like my explanation better.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#57 2014-10-06 05:44:28
Re: Bayes' theorem problem
I did not read your or Calvin's explanation. I like mine better!
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#58 2014-10-07 00:31:49
- Bob
- Administrator
- Registered: 2010-06-20
- Posts: 10,643
Re: Bayes' theorem problem
hi Agnishom,
What site is that ? I'd like to view from the beginning.
Bob
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob
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#59 2014-10-07 00:58:54
Re: Bayes' theorem problem
This is the updated problem
I am a moderator there and I reported the problem for being Kaboobly Doo. So, the problem poser changed the problem now.
Can you solve the new version?
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#60 2014-10-07 01:31:55
- Bob
- Administrator
- Registered: 2010-06-20
- Posts: 10,643
Re: Bayes' theorem problem
Apparently I can. But I see a flaw in the marking system.
I got a/b and computed a times b. But 2a/2b is a perfectly acceptable answer; that would then give the integer 4ab rather than ab. Why does the submitted answer have to be an integer anyway. What's wrong with submitting the decimal value answer, say, in the form 0.something ? Furthermore, it is possible to get the wrong answer and still be marked right eg. if a = 5 and b = 2/5
Bob
ps. I didn't use the Bayes formula. This is because I cannot be bothered to learn formulas ever. I have found that a tree diagram works fine and is easier to explain to others.
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob
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#61 2014-10-07 03:24:18
Re: Bayes' theorem problem
Thanks! I updated the question to state that a and b are relatively prime.
Last edited by Agnishom (2014-10-07 03:32:34)
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
Offline