Poll: A women has two kids, one is a boy, what are the odds the other is also a boy?

[joschen]

Among most mammals, the birth count of males is the highest.

So i am going whit 50%, since there is no higher reasonable option.

 

[DracoSuave]

If you think that it's 33%, then you are wrong.

See, if you accept that there are three outcomes:

Boy/Girl
Girl/Boy
Boy/Boy, then you -are- including the previous event. HOWEVER, there is one problem:

Girl/Boy has a 0% chance of occuring. Because the first child in question is defined as a boy.

So you have three outcomes, of which one has 0% chance of occuring.

The point is, logically excluding an outcome does not alter the chance of that outcome occuring. Just because you can say girl/girl did not happen doesn't change it's probability -of- happening.

Your inability to sort which is which does not affect this.

(altho technically it isn't 50/50 as the chance of a male birth vs female birth is slightly changed)

 

[Gmano]

If you think that it's 33%, then you are wrong.

See, if you accept that there are three outcomes:

Boy/Girl
Girl/Boy
Boy/Boy, then you -are- including the previous event. HOWEVER, there is one problem:

Girl/Boy has a 0% chance of occuring. Because the first child in question is defined as a boy.

So you have three outcomes, of which one has 0% chance of occuring.

The point is, logically excluding an outcome does not alter the chance of that outcome occuring. Just because you can say girl/girl did not happen doesn't change it's probability -of- happening.

Your inability to sort which is which does not affect this.

No... the order in which the boy came wasn't defined. It simply states that one of the children is a boy. Since the thing lacks a 0 option, one should assume that the question means that at least one is a boy, meaning the g/b is a viable option.

 

[Biosophilogical]

0%, first off it starts of stating she HAS (present tense meaning they are already born) two kids, and ONE is a boy. Therefore the other must be a girl.

OT: In all seriousness, heyheysg is right (he is post number 11 jsut for reference)

 

[DracoSuave]

If you think that it's 33%, then you are wrong.

See, if you accept that there are three outcomes:

Boy/Girl
Girl/Boy
Boy/Boy, then you -are- including the previous event. HOWEVER, there is one problem:

Girl/Boy has a 0% chance of occuring. Because the first child in question is defined as a boy.

So you have three outcomes, of which one has 0% chance of occuring.

The point is, logically excluding an outcome does not alter the chance of that outcome occuring. Just because you can say girl/girl did not happen doesn't change it's probability -of- happening.

Your inability to sort which is which does not affect this.

No... the order in which the boy came wasn't defined. It simply states that one of the children is a boy. Since the thing lacks a 0 option, one should assume that the question means that at least one is a boy, meaning the g/b is a viable option.

The order in which the boy came wasn't a part of my argument.

You have: One child, and the other child. The one child, you know because you were told. The other child is the unknown one. The order the children came out is irrelevant. They could have come out at the same time. It does not matter.

 

[Danzaivar]

Just over 50%.

(I read in an article the other day that there are on average 106 men born for every 100 women)

 

[Ziadaine_v1legacy]

50% since it's the male gamete that determines gender.

A second boy, however, does have a 1-2% higher probability of being homosexual. (I WISH I was making that up.)

Later children may not have the potential to grow as large as earlier offspring, and may also suffer intellectually.

You saying homosexuals are small idiots?

not homosexuals, next-in-line children and I think it was scientifically proven that out of some percentage over 50% the first born is generally the smartest of the siblings. I know its not 100% because my friends older brother has stupid written all over his face (and he's not mentally challenged either)

 

[Sun Flash]

Man decides the baby's gender so the woman doesn't really have a choice, but it would be 50% since sex genes are random and not inherited in the same way as say, hair colour.

 

[Blackvegie]

Well, it doesn't matter if more men are born than women because statistically men die younger anyway.

I just realized somebody already mentioned this

 

[orc33]

49.8% looking at the worlds gender ratio

 

[crudus]

The birth of each is an independent event. For simplicity's sake, it's the same as flipping a coin, and we're being asked the chance that we're getting two of a kind. 50% per result for each of 2 results = .5 * .5 = 25% chance that the results will be the same.

So there is a 75% chance that the other child is a girl? That really doesn't add up. It is a 50-50 chance of boy or a girl. It is regardless of how many children she has.

 

[Skeleon]

A trick question our biology teacher used in an exam, funnily enough.
50%, of course, since the first kid is already defined as a boy.
He doesn't matter for the second kid's gender.

Now, if you were to ask "what are the odds both children are boys?" without defining the first one as a boy, then it'd be 25%.

 

[Seldon2639]

50% since the chances of getting a boy or girl in general is based on whether the egg receives either the X or the Y chromosome.

So unless the second child is a fraternal twin, then that is my answer.

You've got it backwards. The egg is always an X chromosome. The sperm is what determines, since it can be either X or Y

 

[Snork Maiden]

Fairly sure that the wikipedia article linked too explained that both the 50% answer and the 33% answer are valid, depending on how you view the question.

 

[SultanP]

Wouldn't we also need to know who the father is and what his semen quality is like?

 

[SultanP]

50% since the chances of getting a boy or girl in general is based on whether the egg receives either the X or the Y chromosome.

So unless the second child is a fraternal twin, then that is my answer.

You've got it backwards. The egg is always an X chromosome. The sperm is what determines, since it can be either X or Y

Actually no, he said it depends on the semen.

 

[Bobular]

We should all agree that the question is badly worded, as apparently there are many different interpretations of it.

That said, I think 50% as we don't care anything about the one we know about and you're over complicating it taking into account different birth-rates, twins etc. without the question mentioning them.