If I have two children, and one of them is a boy, what are the chances that the other one is also a boy?

TruffleSpark

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I saw statistics nerds on twitter arguing about this, they couldn't decide if it was 1/2 or 1/3.
 
The "correct" answer is is 1/3. But only for stupidly pedantic reasons.
The moment you know anything about the boy in question (a famous example being that he was born on a Tuesday), the sample space changes and it goes to being 1/2.
 
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The "correct" answer is is 1/3. But only for stupidly pedantic reasons.
The moment you know anything about the boy in question (a famous example being that he was born on a Tuesday), the sample space changes and it goes to being 1/2.
So 1/3 is the "correct" answer, but only if these children exist in a realm of pure logic. And in actual real world scenarios it would always be 1/2?

This seems like a classic case of autistics not understanding the limits of the models they use to try and simulate reality.
 
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So 1/3 is the "correct" answer, but only if these children exist in realm of pure logic. And in actual real world scenarios it would always be 1/2?

This seems like a classic case of autistics not understanding the limits of the models they use to try and simulate reality.
You didn't respond to my question you gay autistic nigger, was the first born a girl or not?
 
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So 1/3 is the "correct" answer, but only if these children exist in realm of pure logic. And in actual real world scenarios it would always be 1/2?

This seems like a classic case of autistics not understanding the limits of the models they use to try and simulate reality.
Basically.
The sample space in the original question looks like this:
BB
BG
GB
GG
The last one being crossed out because we know they're not both girls. BG and GB are two different outcomes because we aren't told "which one" of the children is a boy. So 2 out of 3 possible outcomes contains a girl.

I would provide a sample space given the Tuesday example, but fuck that. It's easier and not even less accurate to just say that, once you hear "this child" is a boy, you can place him in the first slot making the effective sample space:
BB
BG

It's the same thing going on with that troll question about coin flips. The odds of the other coin being tails given that one is heads is 2/3. But the moment you're actually looking at a heads up coin the probability is just the expected 1/2.
 
Basically.
The sample space in the original question looks like this:
BB
BG
GB
GG
The last one being crossed out because we know they're not both girls. BG and GB are two different outcomes because we aren't told "which one" of the children is a boy. So 2 out of 3 possible outcomes contains a girl.

I would provide a sample space given the Tuesday example, but fuck that. It's easier and not even less accurate to just say that, once you hear "this child" is a boy, you can place him in the first slot making the effective sample space:
BB
BG

It's the same thing going on with that troll question about coin flips. The odds of the other coin being tails given that one is heads is 2/3. But the moment you're actually looking at a heads up coin the probability is just the expected 1/2.
It's 1 if they are monozygotes, retard.
 
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