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/sci/ - Science & Math

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15798880 No.15798880 [Reply] [Original]

Let's say, you've lost a coin flip three times in a row. It landed on heads each single time. Now, when you go flip that coin again, it still has the same 50/50 chance of landing on heads again...

Why? How is it possible? The event of it landing 4 times in a row on heads is highly improbable, so why is it still a fifty fifty, it doesn't make sense, how can the previous events not affect the probability of the new one considering how unlikely it is?

>> No.15798881

>>15798880
If its a fair coin then approximately half of every possible set of coin flips will land on heads.

What the previous, perfectly deterministic, coin tossed were before has minimal impact on the coin tossing system.

>> No.15798883

>>15798881
Still, it doesn't make sense. The probability of it landing on heads 4 time in a row is very low, and yet, the probability of it landing on heads again is the same it ever was, how?
Those two statements put together don't make sense whatsoever.

>> No.15798885

>>15798880
The more heads you got in the row the more likely it is that the coin is biased. Always bet on repeating events.

>> No.15798887

>>15798883
coin tosses are perfectly deterministic like the rest of the universe.

>> No.15798933
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15798933

why is probability such a filter for people? it's still 50/50 because you are rerolling after each coin flip. probability does not add up each time you flip it. if the world worked that way, then you would have a 100% guarantee to win the lottery if you bought 1000 tickets if the odds was 1 in 1000

>> No.15798954

>>15798880
At the time when the coin has been tossed three times, because the outcome of landing on heads has already occurred, the probability that it lands on heads is 1, as opposed to 0.5 (something that has happened cannot not happen). Therefore, the probability of HHHH when three of the heads have already happened is 1 * 1 * 1 * 0.5 = 0.5.

>> No.15799147

>>15798880
it's independant
you'd have to flip them all at once for the probability of 4 heads to be 1/8th

>> No.15799159

>>15798880
>The event of it landing 4 times in a row on heads is highly improbable
It is highly improbable because of tree of possibilities. Each coin flip prunes the branch because possibilities collapsed into one that happened.
That said, IRL casino machines could be programmed to not give prize too often (chance hardcoded into 0 for the next N turns). Regulators won't like this, but not every casino is regulated.

>> No.15799174

The thing is that it is already unlikely that you are in the situation that you landed three heads in a row. Now the last one doesn't need to have that low probability since it was already accounted for by the three throws that you already threw.

>> No.15799199

>>15798880
https://en.m.wikipedia.org/wiki/Gambler%27s_fallacy

>> No.15799213

>>15798880
>The event of it landing 4 times in a row on heads is highly improbable
The event of it landing 3 times in a row on heads and then once on tails is equally improbable

>> No.15799282
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15799282

>>15798880
Say I give you a fair coin. You flip it exactly once(1), and it lands on heads. Do you think it's strange that it landed on heads? No! It had a 50/50 chance after all. Nothing unexpected happened.

Now after you flipped the coin, I hand you a piece of paper. That paper says the coin's previous billion(1,000,000,000) flips all landed on heads. In doing so, did I change the coin in any way? No! Only the information you have, has changed.

The coin doesn't care that you now have a paper with something written on it. The coin isn't keeping track of its previous flips.

>> No.15799295

>>15798880
>Why? How is it possible?
Because each flip is independent. They take no account of the previous result.

>> No.15799299

>>15798880
The chance of any permutation (order of flips matters) is the same. So three heads first and then a tails is just as likely as four heads. Four heads is only unlikely as a combination where order matters as there are less permutations with four heads. But since you've already determined the order the three heads and one tails is just as likely as four heads

>> No.15799330

Most math is just educated guesses. Nobody actually understands numbers, it's just a lot of trial and error.

>> No.15799340

>>15798880
>it still has the same 50/50 chance of landing on heads again
probabilities between 0 and 100 are fake. they're not physically real. the real probability for heads is either 100 or 0, but we can never determine which.

>> No.15799505

>>15798880
Probability is a mathematical concept; the coin is just an illustration, not a description of an actual experiment. In reality, probabilities do not exist.

>> No.15799514

>>15799295
>each flip is independent
there is no evidence for this, it is just an assumption. Probability is a spook, lol, the definition of probability already includes the assumption that the event is probable, and not predetermined.

>> No.15799639

>>15798880
I think, that coins can land on a side. And it happens quite often from numerical perspective.

>> No.15799735
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15799735

>>15798880
The only way is not 50/50 is when the coin is not fair. For pseudo random numbers that can only happen when the period is absurdly short, only then it will be significatively different than 50/50 just after three coin flips.

>> No.15799821

>>15798880
This will be clearer to you if you draw a tree diagram. Remember by the time you're on the 4th toss you are already on a "unlikely" path ("unlikely" in quotes because HHH is equally as probable as HTH etc). You've already thrown HHH so the improbable situation has been generated already. You shouldn't get caught up in conceptual understanding anyways, that will come as you work with the stuff.

>> No.15800148

>>15798887
>perfectly deterministic
Quantum Physics says Hello. There are no hidden variables.