Mike Honcho 4,027 Posted June 19, 2019 John and Jane are a married couple They have two kids, one of them is a girl. Assume safely that the probability of each gender is 1/2. What is the probability that the other kid is also a girl? Share this post Link to post Share on other sites
Voltaire 4,558 Posted June 19, 2019 Normal answer: 0% 2019 answer: Genders are fluid, people who seek to assign constructs of gender based on the body organs present at birth are enforcers of patriarchal oppression. Share this post Link to post Share on other sites
Filthy Fernadez 2,696 Posted June 19, 2019 22 minutes ago, Mike Honcho said: John and Jane are a married couple They have two kids, one of them is a girl. Assume safely that the probability of each gender is 1/2. What is the probability that the other kid is also a girl? .25% Share this post Link to post Share on other sites
bandrus1 413 Posted June 19, 2019 50 percent the events are independent Share this post Link to post Share on other sites
Mike Honcho 4,027 Posted June 19, 2019 13 minutes ago, Voltaire said: Normal answer: 0% 2019 answer: Genders are fluid, people who seek to assign constructs of gender based on the body organs present at birth are enforcers of patriarchal oppression. I'm guessing this is the answer from the Chinese government. Keep guessing guys. Share this post Link to post Share on other sites
Voltaire 4,558 Posted June 19, 2019 3 minutes ago, Mike Honcho said: I'm guessing this is the answer from the Chinese government. Keep guessing guys. The first is the answer : 0%. The second is modernity's LBGTQPZ2 answer. Share this post Link to post Share on other sites
patweisers44 697 Posted June 19, 2019 0%. they have two kids, one of them is a girl. The other isn't a girl then. Share this post Link to post Share on other sites
bandrus1 413 Posted June 19, 2019 Ahh missed that one Share this post Link to post Share on other sites
Mike Honcho 4,027 Posted June 19, 2019 Everyone has still missed it...I'll check back in an hour Share this post Link to post Share on other sites
Mookz 1,287 Posted June 19, 2019 33.3% because you have these possibilities: GB, BG, GG, BB Eliminate BB cuz you know it's not that. That leaves 1 in 3. 1 Share this post Link to post Share on other sites
Mike Honcho 4,027 Posted June 19, 2019 34 minutes ago, Mookz said: 33.3% because you have these possibilities: GB, BG, GG, BB Eliminate BB cuz you know it's not that. That leaves 1 in 3. And Mookz is the winner! He can supply a new one or I'll put up another in a little bit. Share this post Link to post Share on other sites
Mookz 1,287 Posted June 19, 2019 2 minutes ago, Mike Honcho said: And Mookz is the winner! He can supply a new one or I'll put up another in a little bit. Okay, here's one for teh geek bored: Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice? Share this post Link to post Share on other sites
bandrus1 413 Posted June 19, 2019 52 minutes ago, Mookz said: 33.3% because you have these possibilities: GB, BG, GG, BB Eliminate BB cuz you know it's not that. That leaves 1 in 3. this can not be right you know the sex of 1 child F The question is what are the odds of child 2 being F and that is a 50 50 chance regardless of what Child 1 was Share this post Link to post Share on other sites
bandrus1 413 Posted June 19, 2019 I think I need to take 6th grade math again Share this post Link to post Share on other sites
Filthy Fernadez 2,696 Posted June 19, 2019 56 minutes ago, Mookz said: 33.3% because you have these possibilities: GB, BG, GG, BB Eliminate BB cuz you know it's not that. That leaves 1 in 3. BB is not a viable option and GB/BG are the same. It's either GG or GB................. Share this post Link to post Share on other sites
nobody 2,037 Posted June 19, 2019 25 minutes ago, Mookz said: Okay, here's one for teh geek bored: Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice? Always switch. Share this post Link to post Share on other sites
Cruzer 1,992 Posted June 19, 2019 1 hour ago, patweisers44 said: 0%. they have two kids, one of them is a girl. The other isn't a girl then. Forest for the trees..... Share this post Link to post Share on other sites
BiPolarBear 476 Posted June 19, 2019 100% that it is a boy. You already said one of them is a girl; so that just leaves boy. Share this post Link to post Share on other sites
BiPolarBear 476 Posted June 19, 2019 The Fort Worth homies represent! Share this post Link to post Share on other sites
The Observer 641 Posted June 19, 2019 The answer is 50%. Even if a family has 10 girls and 0 boys, the next baby is still a 50% chance. Share this post Link to post Share on other sites
frank 2,144 Posted June 19, 2019 36 minutes ago, Mike Honcho said: And Mookz is the winner! He can supply a new one or I'll put up another in a little bit. It’s 50%. I typed a response to this post but deleted it because I didn’t like the way I worded it. Others have covered it. Share this post Link to post Share on other sites
nobody 2,037 Posted June 19, 2019 16 minutes ago, Filthy Fernadez said: BB is not a viable option and GB/BG are the same. It's either GG or GB................. Seems right to me. Even though the BG and GB cases are the same case, they would happen twice as often as a GG combo. Share this post Link to post Share on other sites
nobody 2,037 Posted June 19, 2019 Here's one. You've been diagnosed with a rare disease. It only occurs in 1 in 10k people. The test for the disease gives a true positive 99.9% of the time. What are your chances of having the disease? Share this post Link to post Share on other sites
Filthy Fernadez 2,696 Posted June 19, 2019 Just now, Mike Honcho said: Boy/Girl Girl/Boy are the same probability given that we weren't factoring in age (boy first then girl or girl first then boy). Share this post Link to post Share on other sites
Cruzer 1,992 Posted June 19, 2019 1 minute ago, nobody said: Here's one. You've been diagnosed with a rare disease. It only occurs in 1 in 10k people. The test for the disease gives a true positive 99.9% of the time. What are your chances of having the disease? If you've already been diagnosed - I'd say 100%. Share this post Link to post Share on other sites
nobody 2,037 Posted June 19, 2019 Just now, Cruzer said: If you've already been diagnosed - I'd say 100%. You can say you've "been told by a doctor" if you prefer that to diagnosed. Share this post Link to post Share on other sites
parrot 789 Posted June 19, 2019 50 minutes ago, Mookz said: Okay, here's one for teh geek bored: Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice? Monty Hall says switch. Share this post Link to post Share on other sites
Mookz 1,287 Posted June 19, 2019 I admit I kind of backed into my answer. It's not intuitive. But the way I justify it in my mind is that if it were 50%, then out in the real world you would expect to find just as many couples with GG as with B and G, and that just don't seem right. Share this post Link to post Share on other sites
jerryskids 5,196 Posted June 19, 2019 18 minutes ago, nobody said: Here's one. You've been diagnosed with a rare disease. It only occurs in 1 in 10k people. The test for the disease gives a true positive 99.9% of the time. What are your chances of having the disease? The answer involves Bayes Theorem but I don't feel like figuring that out. Basically we know the accuracy if you have the disease; the question is the probability you have the disease given the result. Also put me in the 50% camp for the OP, at least how it was worded. Share this post Link to post Share on other sites
Strike 3,968 Posted June 19, 2019 Multiple Events Independent and Dependent Events Suppose now we consider the probability of 2 events happening. For example, we might throw 2 dice and consider the probability that both are 6's. We call two events independent if the outcome of one of the events doesn't affect the outcome of another. For example, if we throw two dice, the probability of getting a 6 on the second die is the same, no matter what we get with the first one- it's still 1/6. On the other hand, suppose we have a bag containing 2 red and 2 blue balls. If we pick 2 balls out of the bag, the probability that the second is blue depends upon what the colour of the first ball picked was. If the first ball was blue, there will be 1 blue and 2 red balls in the bag when we pick the second ball. So the probability of getting a blue is 1/3. However, if the first ball was red, there will be 1 red and 2 blue balls left so the probability the second ball is blue is 2/3. When the probability of one event depends on another, the events are dependent. https://revisionmaths.com/gcse-maths-revision/statistics-handling-data/probability 1 Share this post Link to post Share on other sites
Mike Honcho 4,027 Posted June 19, 2019 20 minutes ago, Strike said: Multiple Events Independent and Dependent Events Suppose now we consider the probability of 2 events happening. For example, we might throw 2 dice and consider the probability that both are 6's. We call two events independent if the outcome of one of the events doesn't affect the outcome of another. For example, if we throw two dice, the probability of getting a 6 on the second die is the same, no matter what we get with the first one- it's still 1/6. On the other hand, suppose we have a bag containing 2 red and 2 blue balls. If we pick 2 balls out of the bag, the probability that the second is blue depends upon what the colour of the first ball picked was. If the first ball was blue, there will be 1 blue and 2 red balls in the bag when we pick the second ball. So the probability of getting a blue is 1/3. However, if the first ball was red, there will be 1 red and 2 blue balls left so the probability the second ball is blue is 2/3. When the probability of one event depends on another, the events are dependent. https://revisionmaths.com/gcse-maths-revision/statistics-handling-data/probability This is Strikes way of saying that I am right, this must be a very very painful day for him. Share this post Link to post Share on other sites
Mookz 1,287 Posted June 19, 2019 The video that Honcho posted is good. The people saying 50% are assuming it's the second case that he goes through, that we already had the girl, and now we're having another baby. But in reality the girl could have been born first or second, which means the boy could also be born either first or second, not just second. Share this post Link to post Share on other sites
Strike 3,968 Posted June 19, 2019 4 minutes ago, Mike Honcho said: This is Strikes way of saying that I am right, this must be a very very painful day for him. Wow, I always knew reading comprehension was a challenge for you, but this seems pretty straightforward. Even Forrest Gump could understand it. Share this post Link to post Share on other sites
Strike 3,968 Posted June 19, 2019 2 minutes ago, Mookz said: The video that Honcho posted is good. The people saying 50% are assuming it's the second case that he goes through, that we already had the girl, and now we're having another baby. But in reality the girl could have been born first or second, which means the boy could also be born either first or second, not just second. It doesn't matter what baby he was talking about in the OP. And I didn't watch the video so not going to comment on it. But having a baby is completely independent of any other baby. The order doesn't matter. The probability of each baby is the same. We're being told that this probability is 1/2. Therefore, it's 1/2 for the first baby, the second baby, and the 1000th baby. Share this post Link to post Share on other sites
Mike Honcho 4,027 Posted June 19, 2019 2 minutes ago, Strike said: Wow, I always knew reading comprehension was a challenge for you, but this seems pretty straightforward. Even Forrest Gump could understand it. The most ironic post ever made at the geek club. You might want to watch the video I posted what you posted shows why the answer is 33%---like I said. So the probability of getting a blue is 1/3. Share this post Link to post Share on other sites
bandrus1 413 Posted June 19, 2019 The question is not worded what is the probability of a couple having a GG The question is what is the probability of the unknown child being a girl. Knowing child 1 has 0 impact on the probability of the unknown child im still saying its 50% Share this post Link to post Share on other sites