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Forum » Math/Philsophy bros GTFIH for a simple problem that will blow your mind
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Thread: Math/Philsophy bros GTFIH for a simple problem that will blow your mind

post 1522858451 10-16-2017, 10:28 PM
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#31
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Originally Posted By FA*******⏩
50-50 from her perspective. The trials with the coin are independent.
From her pov its def 1/3
post 1522858661 10-16-2017, 10:30 PM
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Originally Posted By Reliance012⏩
1/3. Don’t really see the controversy. Can anyone explain a convincing argument for 1/2?
The argument for 1/2 is basically the fact she knows it's a fair coin toss going into the experiment. Once being awoken and interviewed, no new information is being gained here*, from her perspective. Thus it doesn't make sense to change the 1/2 probability for heads.

Why, when you know a certain probability, and then are given no new evidence/information, would you change the estimation of that probability?

*She knowsgoing into the experimentthat she will be awoken and interviewed at some point, so the mere fact that she wakes up is not new information. Also, there is no new information about which day it is, just from being woken up and interviewed. So in totality, no new information is being produced that she didn't have when going into the experiment, at which point she knew the probability was 1/2 for heads.
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post 1522858881 10-16-2017, 10:33 PM
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#33
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1 million and one
post 1522859251 10-16-2017, 10:38 PM
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Pretty sure if I woke up and had to take the biggest chit of my life I'd say 0% it landed heads.
post 1522859811 10-16-2017, 10:46 PM
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She couldve woken up on a Xday (heads), or Xday (tails) or Xday (tails). We put X because the question is asked from her POV, and she has no concept of what day it actually is. On any given Xday, the probability that she was woken up by a tail is twice as likely as a head.

Answer: 1/3

Come at me 50-50 *******s
post 1522860981 10-16-2017, 11:05 PM
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#36
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Her perspective was drug induced and doesn't change the odds or the condition of the experiment. 1/3 brah
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post 1522861561 10-16-2017, 11:14 PM
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#37
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Originally Posted By CrocodileBrah⏩
She couldve woken up on a Xday (heads), or Xday (tails) or Xday (tails). We put X because the question is asked from her POV, and she has no concept of what day it actually is. On any given Xday, the probability that she was woken up by a tail is twice as likely as a head.

Answer: 1/3

Come at me 50-50 *******s
I have seen good arguments for 50-50. For what it's worth, this is more of a philosophical problem than a math problem. Particularly of importance is how one defines probability.
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post 1522861661 10-16-2017, 11:17 PM
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#38
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Originally Posted By KMadigan777⏩
From her pov its def 1/3
You wake up from a coma, knowing absolutely nothing. Someone flips a coin. What is the chance that coin lands on heads?

As far as you know, it's 50-50.

Good problem though, makes you think.
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post 1522861991 10-16-2017, 11:23 PM
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Bottom line is the coin is only tossed one time.

When she wakes up she has no information to form a conclusion she had previously awoken

Answer seems pretty clear.
post 1522862341 10-16-2017, 11:29 PM
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Originally Posted By KMadigan777⏩
From her pov its def 1/3
What makes you say that?
post 1522862461 10-16-2017, 11:31 PM
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Originally Posted By Slurgie⏩
What makes you say that?
Probably a hint of autism.
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post 1522862691 10-16-2017, 11:34 PM
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Lol this is gambler's fallacy 101--kid's stuff. It is obviously 50% odds.

I doubt there is a serious debate, but please provide sources.

There are people that debate the gamblers' fallacy--on the Internet. There are also people--on the Internet--who believe the earth is flat.
mo e
post 1522863321 10-16-2017, 11:44 PM
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switch(heads) {
case Monday: return .5;
case Tuesday: return .5;
case Wednesday: return .5;
}

No matter what it's always 50/50 because the coin was flipped one time. What am I missing, OP? I don't see how it could even be 1/3
post 1522863681 10-16-2017, 11:50 PM
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#44
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Originally Posted By iceypain⏩
bayesian probability

1/3

question is not "heads or tails", it's "given that i've been woken up, was it heads or tails?"
Thanks for simplifying. So you're saying 3 is the denominator because it's the number of possible times waking?
Originally Posted By KMadigan777⏩
Exactly, and if you know that scenario, you should see why the right answer to this is 1/3.

Imagine a similar problem, if its heads, you wake up once, asked question, then go to sleep until its over. If its tails they wake you up 1000 times to ask you a question before its over. Whats more likely, they are talking to you, and its its the 1/1000 that it was heads, or 999/1000 that this is just a tails interview?
This is a really interesting way of looking at it. So how do you get 1/3 from 50-50? I'm asking conceptually/mathematically
post 1522863881 10-16-2017, 11:52 PM
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#45
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Originally Posted By KMadigan777⏩
Exactly, and if you know that scenario, you should see why the right answer to this is 1/3.

Imagine a similar problem, if its heads, you wake up once, asked question, then go to sleep until its over. If its tails they wake you up 1000 times to ask you a question before its over. Whats more likely, they are talking to you, and its its the1/1000 that it was heads , or 999/1000 that this is just a tails interview?
Or is it still just the 1/2 and not 1/1000. Why consider all the extra tails wakeups when she knows that her wakeup, of which she has no information about, could easily have been the other half of the 50/50 coin flip?

Take your example further for emphasis and say there were a billion (10^9) wake ups for tails, and 1 for heads. Say you were awoken as in the experiment. And then it was revealed it was heads. Would you really be so shocked that some astronomical chance (about 1 in a billion) happened? I don't think I would be, given the premise of the experiment- it was just the other half of the 50/50 coin flip.
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post 1522864051 10-16-2017, 11:54 PM
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#46
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But who's giving sleeping beauty the D?
post 1522864101 10-16-2017, 11:55 PM
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You wake her up twice as many times when it's tails so of course it's better odds to say tails.... If it's tails and she always says tails then she's right twice. If it's heads and she always says tails then she is wrong once.
post 1522864341 10-16-2017, 11:58 PM
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#48
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I don't see why what happens after the flip is of any relevance. The odds of the coin landing on either outcome is 50:50.
Bald head scallywag
post 1522864591 10-17-2017, 12:01 AM
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#49
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This question/riddle deals with a known phenomenon in physics called frame of reference. The question poses 1 question but dealing with two frames of reference. That is the problem.
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post 1522865491 10-17-2017, 12:13 AM
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#50
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Originally Posted By dbluevette⏩
This question/riddle deals with a known phenomenon in physics called frame of reference. The question poses 1 question but dealing with two frames of reference. That is the problem.
I'm failing to see how frame of reference changes mathematical probability of a given outcome. Either this is a question of math or it's a question of perspective. Not both, math is not subjective.
Bald head scallywag
post 1522865601 10-17-2017, 12:15 AM
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#51
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Originally Posted By BearTactics⏩
I'm failing to see how frame of reference changes mathematical probability of a given outcome. Either this is a question of math or it's a question of perspective. Not both, math is not subjective.
Same math, just different frame of reference.
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post 1522866281 10-17-2017, 12:26 AM
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Originally Posted By dbluevette⏩
Same math, just different frame of reference.
Frame of reference has no bearing on the math. She could've gotten woken up 1M times. She also could have gotten woken up once. The probability of either scenario is exactly the same given a fair coin.
Bald head scallywag
post 1522866621 10-17-2017, 12:33 AM
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#53
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Originally Posted By BearTactics⏩
I'm failing to see how frame of reference changes mathematical probability of a given outcome. Either this is a question of math or it's a question of perspective. Not both, math is not subjective.
In probability theory you can have conditional probability. For example, in picking a random card from a 52 card deck, the probability of it being a heart is 1 in 4. However, the probability of it being a heart given that it is a red, is changed to 1 in 2. The difference here, of course, is that the "given red" is adding new information.

When we ask what is the probability of heads given she wakes up and is interviewed, the "waking up and being interviewed" is not adding any new information to change the 1/2 probability
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post 1522866651 10-17-2017, 12:33 AM
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Originally Posted By BearTactics⏩
Frame of reference has no bearing on the math. She could've gotten woken up 1M times. She also could have gotten woken up once. The probability of either scenario is exactly the same given a fair coin.
dammit this is hurting my heads
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post 1522868311 10-17-2017, 01:04 AM
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IMO 1/2. The number of possibilities are less important than the flip of the coin. The flip of the coin is the governing action here.
post 1522868561 10-17-2017, 01:08 AM
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Who cares about this stupid thot? Probably best you stay away because after you wake her up she's gonna be tweeting this #MeToo nonsense, dumb sloot.
post 1522868631 10-17-2017, 01:10 AM
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Originally Posted By NVious⏩
Who cares about this stupid thot? Probably best you stay away because after you wake her up she's gonna be tweeting this #MeToo nonsense, dumb sloot.
lmao
post 1522868731 10-17-2017, 01:12 AM
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Originally Posted By numberguy12⏩
In probability theory you can have conditional probability. For example, in picking a random card from a 52 card deck, the probability of it being a heart is 1 in 4. However, the probability of it being a heart given that it is a red, is changed to 1 in 2. The difference here, of course, is that the "given red" is adding new information.

When we ask what is the probability of heads given she wakes up and is interviewed, the "waking up and being interviewed" is not adding any new information to change the 1/2 probability
being woken up is new information. the outcome of the coin flip affects the likelihood of her being woken up.
post 1522868921 10-17-2017, 01:15 AM
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Originally Posted By iceypain⏩
being woken up is new information. the outcome of the coin flip affects the likelihood of her being woken up.
Being woken up is not new information. She knew before even going into the experiment that she would be woken up at least once. So merely waking up is not new information.
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post 1522869181 10-17-2017, 01:18 AM
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I have a good feeling the misc is going to figure this out shortly.
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