/sci/ - Science & Math » Thread #11372644

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Anonymous Sun 09 Feb 21:38:31 2020 No.11372644 View Reply Original Report

Quoted By: >>11372691 >>11372855 >>11373606 >>11375085 >>11375108 >>11375714

its 1/3 chance right? thats what I recall from that one movie "21"

Anonymous

Anonymous Sun 09 Feb 2020 21:50:44 No.11372691 Report

Quoted By:

>>11372644
(a) 1/3
(b) 1/2
(c) 1/2

Anonymous

Anonymous Sun 09 Feb 2020 22:44:02 No.11372855 Report

Quoted By: >>11372887

>>11372644
(A)
Two children O and P. Possible configuration of gender for any two kids are:
MM
MF
FM
FF
At least one is a boy so FF is eliminated.
Any three of the remaining configurations are possible, and MM is a 1/3 chance.

Anonymous

Anonymous Sun 09 Feb 2020 22:52:28 No.11372887 Report

Quoted By: >>11372937 >>11373028

>>11372855
But FM and MF in this scenario are effectively the same permutation are they not?

Anonymous

Anonymous Sun 09 Feb 2020 22:57:53 No.11372906 Report

Quoted By: >>11372925 >>11373013

"boy" and "girl" fall on a continuous distribution so the probability of each is zero

Anonymous

Anonymous Sun 09 Feb 2020 23:04:04 No.11372925 Report

Quoted By: >>11373013

>>11372906
Doesn't follow; 'girl' and 'boy' are not isolated points on this distribution.
However, the question doesn't specify that
a) 'boy' and 'girl' have almost-no overlap
b) the union of 'boy' and 'girl' has almost-no events outside it

Nonetheless, it is clearly implied

Anonymous

Anonymous Sun 09 Feb 2020 23:09:00 No.11372937 Report

Quoted By:

>>11372887
Uhh, you might be right actually. I'm not sure.

Anonymous

Anonymous Sun 09 Feb 2020 23:51:35 No.11373013 Report

Quoted By:

>>11372906
kek i see what you did there

>>11372925
>a) 'boy' and 'girl' have almost-no overlap
>b) the union of 'boy' and 'girl' has almost-no events outside it
that is hatespeech in the eyes of the gender studies professor

Anonymous

Anonymous Sun 09 Feb 2020 23:59:59 No.11373028 Report

Quoted By: >>11373192

>>11372887
No because there are two different children, one of whom is a boy.
3 possibilities:
1. both of them are boys (1/3)
2. only the older one is a boy (1/3)
3. only the younger one is a boy (1/3)

Anonymous

Anonymous Mon 10 Feb 2020 01:08:13 No.11373192 Report

Quoted By: >>11373253 >>11375054

>>11373028
Older or younger? That wasnt mentioned in A. There are only two choices: one of them is male or two of them are male. It doesnt matter which one is male or female.

Anonymous

Anonymous Mon 10 Feb 2020 01:36:02 No.11373253 Report

Quoted By: >>11373549

>>11373192
>Older or younger? That wasnt mentioned in A.
The fact that out of 2 children one of them has to be older than the other has to be mentioned in the question?

>There are only two choices: one of them is male or two of them are male

And the former is twice as likely

If you have 2 children, there is a 50% chance of you ending up with 1 boy 1 girl, 25% chance of you ending up with 2 boys and 25% with 2 girls.

Anonymous

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Anonymous Mon 10 Feb 2020 04:25:36 No.11373549 Report

Quoted By: >>11373562

>>11373253
Age is literally never mentioned so stop bringing it up. So, you know that one of them is male already. Now you have two options left. The other one is male or the other one is female. There are no other options. that means that there is a 50% chance that the other child is male.

Anonymous

Anonymous Mon 10 Feb 2020 04:32:58 No.11373562 Report

Quoted By: >>11373600

>>11373549
I'm not gonna bother with you further, you are pretty much math illiterate.

Anonymous

Anonymous Mon 10 Feb 2020 04:50:20 No.11373593 Report

Quoted By: >>11373597 >>11373607

I don't get. How is it that a), b) and c) are any different? In all the three problems you're working with a conditional probability: calculate the probability that the second child is a boy given the first was a boy too. In all three cases is 1/3. Am I wrong?

Anonymous

Anonymous Mon 10 Feb 2020 04:52:56 No.11373597 Report

Quoted By: >>11373604

>>11373593
Yes

Anonymous

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Anonymous Mon 10 Feb 2020 04:54:11 No.11373600 Report

Quoted By:

>>11373562
Or maybe you just took a bad college pill

Anonymous

Anonymous Mon 10 Feb 2020 04:55:53 No.11373604 Report

Quoted By:

>>11373597
Care to explain why?

Anonymous

Anonymous Mon 10 Feb 2020 04:56:36 No.11373606 Report

Quoted By:

>>11372644
For a, in a regular conversation, it is extremely likely the next one is a girl, otherwise it might have been said that both were boys. I don't know how many possible formulations there may be for merely stating child 1 is x, child 2 is y but I suspect there are many even if we include only terse descriptions. I guess this sort of thinking probably goes against the spirit of the problem.

Anonymous

Anonymous Mon 10 Feb 2020 04:56:55 No.11373607 Report

Quoted By: >>11373614

>>11373593
>calculate the probability that the second child is a boy given the first was a boy too.
That would actually be 1/2, because you have some form of order there

In a) you are calculating the odds of both being boys, knowing at least one of them is a boy. An easier way of understanding is calculating the odds of both being boys when you are given the information that both of them being girls is not an option.

Anonymous

Anonymous Mon 10 Feb 2020 05:04:00 No.11373614 Report

Quoted By:

>>11373607
FUCKING THANK YOU YOU ARE THE ONLY OTHER SMART PERSON IN THIS THREAD

Anonymous

Anonymous Mon 10 Feb 2020 19:54:21 No.11375054 Report

Quoted By: >>11375112

>>11373192
>Older or younger?
Any given child will always be either older or younger than its sibling, unless they are Siamese twins. The point is that each child is a separate unit.
Ok, on the off chance they are Siamese twins, let's just refer to them as child A and child B.
The possibilities are:
1. Child A and B are both boys (1/3)
2. Only child A is a boy (1/3)
3. Only child B is a boy (1/3)

Anonymous

Anonymous Mon 10 Feb 2020 20:11:51 No.11375085 Report

Quoted By:

>>11372644
The stranger is a schizophrenic because you're supposed to say "sorry" or "excuse me" when you bump into someone and not make categorical statements about your children

Anonymous

Anonymous Mon 10 Feb 2020 20:25:27 No.11375108 Report

Quoted By:

>>11372644
its 50/50 why is there so much debate?

Anonymous

Anonymous Mon 10 Feb 2020 20:28:25 No.11375112 Report

Quoted By:

>>11375054
you failed because you didnt read the question

Anonymous

Anonymous Tue 11 Feb 2020 00:32:10 No.11375714 Report

Quoted By:

>>11372644
1/4 two-child pairs are G,G
1/4 two-child pairs are B,B
1/2 two-child pairs are G,B

So 1/3 of two-child pairs with at least one boy are B,B
2/3 of two-child pairs with at least one boy are G,B.

B and C are trivially 1/2.

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