Off-Topic

[BurghFan]

re: Off-Topic

My math student has given me a "probability" problem that has stumped me:

There are two families, family A and family B. Both of them have two children. Family A has a boy who plays football, and the other child likes to swim. Family B has a 5-year old boy and a newborn. Which family is more likely to have a girl? Why?

Here have been my guesses so far, just pasted from my e-mails back to him:

Spoiler

I'll guess that it is Family A. My reasoning will be because if one likes to play football, it would have been possible or likely that the other would like to play football as well. Instead, the other individual does an activity that is far different than the other, in that the influence of one didn't seem to promote the influence of the other (plus we don't know how old that second child is, which could be older than that boy).

I don't truly truly believe that, but that is the fairest reasoning I could come up with. That doesn't necessarily mean girls like to swim more than guys or anything like that, but whatever haha.

He said that was wrong. Then I looked more at the age factor and made my second attempt:

Spoiler

Well then my next best guess is that because Family A's children has a chance of being twins, and you are more likely to have identical twins than fraternal twins, that it means there is that small increased likelihood that both of them are boys instead of one boy and one girl... so Family B is more likely to have a girl haha.

Also said was incorrect, that I was overthinking it, but that it did have to do with the ages. So my final crack so far is this:

Spoiler

Since Family A has "established" children (so much so that they already have interests which require a little more physical exertion than a toddler's walk), it is safe to assume that they are at least somewhat older... even if seven years old or so, if not older than that.

Anyway, maybe there is something that statistically shows (I have no idea) a family is more likely willing to have another child if they would like the other gender, and said family is willing to settle if they have one child of each gender.

As Family B just had their newborn and the probability is about 50/50 of being a girl, it's more likely that Family A has a girl because it has been quite some years before they have birthed another child, perhaps because they are settled on the outcome of their own... a boy and a girl.

... to which he also said is not only incorrect, but I am still way overthinking it. I mean, clearly I am. I'm aware of that fact. That's because I can't think of any simple answers to this.

Maybe it's one of those kinds of problems that doesn't require a math mind, but one of those "Five-year-old's answered this with a higher success rates than adults." I mean I don't actually think there is any sort of probability involved (not that anything I did was real-real probability to begin with, but still).

Can anyone else take a crack at this, tell me what I'm missing or go for your own answer here?

I would say both families have a 50% chance of having a girl simply because any fertilized zygote has equal 50% chance of having 46,XX (female) or 46,XY (male) chromosome complement. There are a few things that could skew that ratio, but that's getting into complex genetics. Interests are a really poor predictor of gender and sex of any child is regardless of birth order is independent of sex of all other children.

[Blzer]

re: Off-Topic

I would say both families have a 50% chance of having a girl simply because any fertilized zygote has equal 50% chance of having 46,XX (female) or 46,XY (male) chromosome complement. There are a few things that could skew that ratio, but that's getting into complex genetics. Interests are a really poor predictor of gender and sex of any child is regardless of birth order is independent of sex of all other children.

I'd agree mostly with this, but based on the way that he's asking it sounds like there is an actual answer to this that isn't just: "It's a tie, stupid."

Maybe I should first ask him if it is or not, though...

[kehlis]

re: Off-Topic

I'd agree mostly with this, but based on the way that he's asking it sounds like there is an actual answer to this that isn't just: "It's a tie, stupid."

Maybe I should first ask him if it is or not, though...

Nah, to me, it sounds like it's a loaded question. Don't know your relationship with this student but it's almost like a questions trying to bade you into a stereotypical conversation because that what the question is.

[dickey1331]

re: Off-Topic

Maybe it has to do with the wording. And the other child versus and a newborn?


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[Blzer]

re: Off-Topic

Nah, to me, it sounds like it's a loaded question. Don't know your relationship with this student but it's almost like a questions trying to bade you into a stereotypical conversation because that what the question is.

You could be onto something. He's a pretty clever kid, and I wouldn't put it past him to do something like that. He's likes to throw math riddles at me, but this is the first one he's done that doesn't seem very mathematical.

Maybe it has to do with the wording. And the other child versus and a newborn?

Are you suggesting the newborn is not necessarily human?

EDIT: Wait, that came out stupid. Even dogs have genders lol.

[dickey1331]

re: Off-Topic

Maybe by saying and the other child is meaning it’s a girl?


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[BurghFan]

re: Off-Topic

I'd agree mostly with this, but based on the way that he's asking it sounds like there is an actual answer to this that isn't just: "It's a tie, stupid."

Maybe I should first ask him if it is or not, though...

Perhaps that's the "trick" in the trick question. It's deliberately worded to make it seem like the obvious answer isn't the correct one when in fact it is.

[Blzer]

re: Off-Topic

He e-mailed me back and said the probabilities are not equal. He also said:

"Think in the range of: Knowing there are two children, what are the possible outcomes that have a girl (do this for each family). Its in the 'simplicity range' of x/y, where x and y are integers."

I... I don't get it, and math is my forte.

[dickey1331]

Off-Topic 2018

Yeah you have a 51% chance of having a girl if you average it out. If both have a boy you’re likely to have a girl next on average. I don’t see how that helps


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[WaitTilNextYear]

re: Off-Topic

On a serious note that display case is nice. Where did you pick it up?

The appearance of Todd Packer makes this gif for me.

My math student has given me a "probability" problem that has stumped me:

There are two families, family A and family B. Both of them have two children. Family A has a boy who plays football, and the other child likes to swim. Family B has a 5-year old boy and a newborn. Which family is more likely to have a girl? Why?

Can anyone else take a crack at this, tell me what I'm missing or go for your own answer here?

This is where you do like James T. Kirk and rig the test. Kobayashi Maru time.

See there's also Family C, which has two children. And both girls. Accordingly, I vote for Family C over A and B because p(having a girl) = 1.

[l3ulvl]

re: Off-Topic

I thought about going that route, but the couch sounds better than the car, the floor, the pool, or the driveway.

I would not recommend sleeping in the pool

[l3ulvl]

re: Off-Topic

I love the idea of Blzer's students distracting him with brain teasers while they conduct nefarious activities

[slickdtc]

re: Off-Topic

My math student has given me a "probability" problem that has stumped me:

There are two families, family A and family B. Both of them have two children. Family A has a boy who plays football, and the other child likes to swim. Family B has a 5-year old boy and a newborn. Which family is more likely to have a girl? Why?

It’s Family A.

Both families have a boy, but Family B’s ages are revealed (5 year old, newborn). We don’t know how old either child of Family A’s is. This is key.

What they don’t say is that this girl must be birthed by Family A or B’s parents... just which “family” is more likely to have a girl. Family could be grandchildren too, like the children the football boy or “other child” of Family A could have. Remember, even grown adults are “children” of their parents.

Since Family B has young children, they aren’t capable of having kids of their own yet. Family A has children that could potentially be older (and it seems implied by their interests), and therefore could have birthed children of their own, giving them a more likely chance of having a girl within their family.

[Blzer]

re: Off-Topic

^ You may be onto something. Just tell me if this question I asked him upsets that (this is the first thing I asked him before attempting to solve it):

"Are you talking about each family having a THIRD child and you're asking if that would be a girl, or are you asking of the SECOND child that is mentioned is a girl?"

To which he said:

"It's asking about the second child, not some new third child."

However, you got me thinking about the fact that that other child could be adopted, and the family could have selected a girl at any time by that route. I might ask him if that is what it has to do with.

[jeremym480]

re: Off-Topic

For all the folks that like Funko Pops...

whatever you do, don't look up QMX figures.

I didn't know what these where and I just looked them up when I read this yesterday. Ironically, I bought some pop's off of a guy in a Funko FB group last week and he checked back with me last night. We started talking and it turns out he's a toy photographer. Check out his Instagram: https://www.instagram.com/the_fock_one_/