Coin Flip Odds

Makes sense. Per my aforementioned article: "Diaconis himself has trained his thumb to flip a coin and make it come up heads 10 out of 10 times."

Not so bad, eh?

But what happens if my opponent has the coin and makes me call? I'm doomed. It's like a nightmare. It'll just keep getting worse and worse.

hang-the-9 said:
Here is how you control the coin flip. You toss it. Preactice tossing it at a certain speed, much like a juggler. You can count and influence the rotation amount, to a pretty close estimation of how it flips. Practice for a long time, you should be able to increase the 50% odds by a bit. Enough to bet on it for a while and come out ahead.

I tried this a while back, I got it so if I toss it about 6 inches up, I got it correct about 70% of the time. The bounce when it lands is a bit unpredictable still.
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Jaden said:
I know that the accepted paradigm is that there is always a 50% chance, but I am trying to elicit some higher level thought here.

In reality, there is not a 50 percent chance that it will land heads or tails, even with all kidding aside about the chances of it landing on it's side. Seriously, the chances are only 50% in your head. It is an abstract concept that the coin flip is random. IT ISN'T. But since we are dealing with an unsubstantiated premise that the coinflip is 50%, then my argument is valid. It is valid because it TOO is an unsubstantiated premise but it is logically sound. Again, the reality of each coinflip not having a REAL influence on the outcome of the next flip is moot, because we are dealing with an abstract thought or premise that the coinflip is 50%. I can use the same argument that the coinflip isn't truly random to throw your premise that it is 50% out the window, so you can't use the argument that there is no future influence.

Without that argument, can you discount the predictibility of future tosses?

The answer is, no you can't. So we are stuck, you are right and wrong, as am I. It is not 50% but if we accept that it is as a given, then my premise that I can more accurately predict the next outcome with knowledge of prior outcomes is logically sound and valid.

Jaden
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Well, if you are now creating a different hypothetical, one where the the coin toss is somehow being influenced in some fashion, and is not random, then we have a entire different discussion....it's called cheating.

Really Jaden, the coin has no memory and each individual toss, bar cheating, and the outcome is 50/50....there are only two random outcomes.

Good night.

Jim
 
you can do it with computer modeling because there is truly no randomness

If you were to use computer modeling that is designed to be truly fifty/fifty but also give random results on any given toss, then I can predict with greater than 50% accuracy what a given toss would be if the past results were skewed. That is because there would be an outside influence, the software, that is affecting future results. The premise that it is truly 50% creates the influence on future results.

That is the point that I am trying to make. Your premise that a coinflip is 50% creates the influence on future results, because that premise requires that eventually it is evened out. In reality, the coinflip is NOT 50% so it has no such requirement, but given the falsly created premise that it IS 50%, my argument is valid. Do you see what I'm saying yet???


Jaden
 
Jaden said:
If you were to use computer modeling that is designed to be truly fifty/fifty but also give random results on any given toss, then I can predict with greater than 50% accuracy what a given toss would be if the past results were skewed. That is because there would be an outside influence, the software, that is affecting future results. The premise that it is truly 50% creates the influence on future results.

That is the point that I am trying to make. Your premise that a coinflip is 50% creates the influence on future results, because that premise requires that eventually it is evened out. In reality, the coinflip is NOT 50% so it has no such requirement, but given the falsly created premise that it IS 50%, my argument is valid. Do you see what I'm saying yet???


Jaden
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No, but pass the bong.
 
Wrong Again!!!!!!

jimmyg said:
Well, if you are now creating a different hypothetical, one where the the coin toss is somehow being influenced in some fashion, and is not random, then we have a entire different discussion....it's called cheating.

Really Jaden, the coin has no memory and each individual toss, bar cheating, and the outcome is 50/50....there are only two random outcomes.

Good night.

Jim
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Because there is no memory it cannot be 50/50. It can only be what it is. If the premise that it IS 50/50 is accepted then there is a memory and it CAN be predicted.


Jaden
 
I am not nor have I ever been high.....

punter said:
No, but pass the bong.
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I'm sorry that you're not capable of following advanced courses of logic. It is premises like these that schools should be teaching instead of B.S. like they do.

Jaden.
 
Dont let it bother you. Its just a streak of bad luck on the coin flips. If you let it get to you, it can affect your play and cost you money. JMO.

Southpaw
 
I am actually an accomplished poker player...

sydbarret said:
Don't take up poker.
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I have even been mentioned in Card Player for winning a qualifier to the WSOP where I did quite well. I have won several smaller tournaments as well.

Jaden....

p.s. anytime you want to play me some, I'll be happy to....
 
Jaden said:
Because there is no memory it cannot be 50/50. It can only be what it is. If the premise that it IS 50/50 is accepted then there is a memory and it CAN be predicted.


Jaden
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Eliminating the possibility that the coin can land on it's side, which does change the probabilities, there are only two random possibilities, they are not premises, but actual possibilities. It's 50/50 for each INDIVIDUAL toss, and the coin has no memory of prior tosses. It's really very simple, and not worthy of a doctoral dissertation.

Sometimes a cigar is just a cigar.:rolleyes:

Good night again.

Jim
 
StevenPWaldon said:
Makes sense. Per my aforementioned article: "Diaconis himself has trained his thumb to flip a coin and make it come up heads 10 out of 10 times."

Not so bad, eh?

But what happens if my opponent has the coin and makes me call? I'm doomed. It's like a nightmare. It'll just keep getting worse and worse.
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The way to stop undue influence is to call it in the air. Your chances of getting the right call are way lower that way even if you control the flip. But.. it not back to 50/50. Lets say you toss normally.. 50/50.. if your opponent picks 50/50 between heads or tails then the chance of both the toss and the pick to match are less than 50%. If you toss to 100% heads.. your opponent picks 50% heads.. you are at a higher probablility of winning, as he has no control over heads or tails, and is going by the idea that it's random. So he is just as likely to pick tails over heads, although you know it is always heads. Overall you are increasing your chances even though you lost one of the factors to control.

For total true randomness take into account the air current, surface elasticity when it hits, what area of the finger you are using to flip (if you use the rounded part it will leave the finger at a different angle than if you toss if off your nail), so to have true 50% chances, all of those have to be controlled. You basically need to toss a flat disk in a vaccum onto a perfect surface (no give and lots of friction to hold the coin) to hit a true 50%.
 
I's take the bong after all this talk is making me go dumdum and want to sit on my bumbum..:rolleyes:

Are we talking quaters, dimes, nickels, or pennies. I prefer to use dice you call high or low or use a pair and play craps for the break....

come on lucky number 7????
 
actually that would be 100%

PoolBum said:
Indeed, I believe the probability that any given cigar is just a cigar is in fact 50/50.
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A cigar being just a cigar is actually 100%
 
Between the "tree falling in the forest" and the "chaos theory", my head hurts!

However, following up on a posters comment on the flipper's ability to effect the outcome, an old hustler friend of mine taught me how to flip a coin with great accuracy, but of course it's a trick....and one I got quite good at with a little practice and a quarter or larger coin. My friend could do it with any size coin, but he was a truly talented conman.

The basic idea is that when you "flip" it with your thumb in the customary manner, you catch an edge but don't actually "flip" it, but rather toss it upward spinning it with a large wobble like a wobbling spinning plate. The wobble of a shiny coin gives the illusion of it turning end over end when in fact is is just a severe "wobble" in the coin and whatever side was facing up remains up. So, if it was tails up and the caller called tails you caught it and flipped it over onto the back of your wrist and heads would be up....if he called heads you just caught it in your palm and closed your other hand over it, retaining the tails up position.

If you get it wrong it goes up flat as a pancake, spinning..and might get your thumbs broken though so first...practice, practice, practice.

Oh, and Fatboy......"tails"........:)

Joe
 
punter said:
Sorry, don't agree here, each coin flip is an independent trial. Past flips don't influence future flips. Counting cards on the other hand, is dependent on what cards have been removed and which ones remain. If you flip 20 heads in a row, the odds on the next flip is still 50/50.
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You are correct. Jaden is right that in any particular SERIES of coin tosses, the odds are against an equal outcome.

But you are correct that in spite of an unequal count along the way, EACH "fair" toss has a 50/50 probability.

Just google "coin toss probabilities" and you will get a lot of interesting hits such as:

The following is the probability associated with 1 unbiased coin being tossed n time(s) in succesion and the result recorded. The order of the results are relevant. There are 2 outcomes per coin toss, heads or tails. Each coin toss does not affect the outcome of further tosses.

The formula to calculate the number of possibilities is:
P = 2n

The formula to calculate the probability of a single result is:

P = 1
--------------------------------------------------------------------------------
2n


Where n is the number of tosses. All possible results have the same probability.
http://www.knowyourluck.com/coinsno.html
 
Coin Toss

I once lost nine coin tosses in a row for 50$ a toss. The crazy thing, I called heads everytime; I was sure it had to land on heads sooner or later, it never did!
 
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