Coin flip not random

Page 2 - Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.

JulesMaximus

No Lifer
Jul 3, 2003
74,584
984
126
Originally posted by: Arcadio
I knew that. That's why I use random.org every time I need a random event instead of a coin flip.

What if you're not near a computer? Oh wait, this is ATOT...nevermind.
 

DrPizza

Administrator Elite Member Goat Whisperer
Mar 5, 2001
49,601
167
111
www.slatebrookfarm.com
That was a rather interesting research paper. I think the 51% claim is taken a little out of context.
Conclusion:
Despite these important caveats we consider the bias we have
found fascinating. The discussion also highlights the true difficulty of carefully studying
random phenomena. If we have this much trouble analyzing a common coin
toss, the reader can imagine the difficulty we have with interpreting typical stochastic
assumptions in an econometric analysis.
The caveats and analysis also point to the following conclusion: Keller?s analysis
gives a good approximation for tossed coins. To detect the departures of the order of
magnitude we have found would require 250,000 tosses. The classical assumptions of
independence with probability 1/2 are pretty solid.

You can read the entire paper here:
http://www.stat.berkeley.edu/u.../diaconis_coinbias.pdf
(You're welcome, for the 5 of you who may actually read it.)
 

DrPizza

Administrator Elite Member Goat Whisperer
Mar 5, 2001
49,601
167
111
www.slatebrookfarm.com
Also, for what it's worth, their analysis did not include for the coin to bounce on the table or on a floor. The coin has to be caught.

That's pretty amusing, because I can flip a coin and have it come up heads 100% of the time, or tails 100% of the time, if you're going to let it land in my hand (sucker!)
 

Jeff7

Lifer
Jan 4, 2001
41,596
20
81
Originally posted by: Fox5
Originally posted by: her209
Originally posted by: mundane
Originally posted by: Arcadio
I knew that. That's why I use random.org every time I need a random event instead of a coin flip.
Okay, I'll bite. Why would you need a random number in your daily life?
Fake phone number

I've been using python's random class to generate a random number whenever I needed one. Generally for choosing maps in multiplayer games.

I use an electronic dice roller (LEDs that light up) that I made for general random decisions throughout my life. It doesn't really give random output though.
(minor thread-jack)
Any thoughts on this?
Its claim:
This may well be the world's only discreet logic circuit to generate truly random output.
The 200Hz oscillator samples the phase noise of the 2MHz oscillator yielding a truly random coin-toss output.

It might become a side project eventually.
I've tried a few commercially-available LED candles, and I've found this:
Philips LED candles don't flicker. They blink. It's very obvious that it's nothing close to a candle.
Various other candles that come close to a flickering behavior seem to have a repeating pattern after a minute or so, similar to cheap white noise generators. Two of them side by side will eventually sync up, much like turn signals which are timed with different frequencies; at certain points in the cycle, they appear to nearly sync up.


I've also heard that a cheap way to create random noise is to take a CCD, enclose it in a completely dark, cold container, and boost its gain. The static generated would then be random, the product of electron vibration or motion, or some such thing.



Originally posted by: Regs
This is like...multiplying any number by 0.
Uh oh


 

SunSamurai

Diamond Member
Jan 16, 2005
3,914
0
0
Originally posted by: GodlessAstronomer
Originally posted by: SunSamurai
What the hell? Coins arnt separate from the laws of nature?

But... they are COINS.

Read the full article, that's not the point. The main conclusion here is that when human beings flip coins, the outcome isn't random. Traditionally we have assumed that the outcome should be essentially random due to chaos theory - small differences in the initial conditions lead to large variations in how the coin behaves. This article shows that this doesn't lead to true randomness.

Yeah no shit, that's what I was implying. Nothing is truely random. Random cannot exist. Even things like the uncertainty principle only apply to human capability to measure, they do not extend to what actually is.

A toss is only random enough because we have no practical way to determine it before hand. That doesn't mean its not governed by strict laws
 

moparacer

Golden Member
Dec 10, 2003
1,336
0
76
Funny this topic should come up this week.

I was at the drag races Saturday night and when you and your opponent want the same lane you have to flip a coin for lane choice. I never really give much thought to the whole coin flip process and while he was looking for a quarter I decided since I had called heads the last 3 times and won, I would call tails this time....

He flipped it, it came up heads, and I ended up losing the round.......

randomness fail
 

Born2bwire

Diamond Member
Oct 28, 2005
9,840
6
71
Originally posted by: moparacer
Funny this topic should come up this week.

I was at the drag races Saturday night and when you and your opponent want the same lane you have to flip a coin for lane choice. I never really give much thought to the whole coin flip process and while he was looking for a quarter I decided since I had called heads the last 3 times and won, I would call tails this time....

He flipped it, it came up heads, and I ended up losing the round.......

randomness fail

Another victim of the gambler's fallacy.
 

BeauJangles

Lifer
Aug 26, 2001
13,941
1
0
Originally posted by: SunnyD
I've come to a science myself flipping coins. Using my technique, I can influence the outcome to about a 75% accuracy.

Yeah, I flipped lots of coins in high school and was able to influence the result of the flip significantly by practice. The key is to keep the spinning controlled and precise. I'd say that I could get a coin to land on the same side as the initial side nearly 70% of the time.
 
Oct 27, 2007
17,009
5
0
Originally posted by: SunSamurai
Originally posted by: GodlessAstronomer
Originally posted by: SunSamurai
What the hell? Coins arnt separate from the laws of nature?

But... they are COINS.

Read the full article, that's not the point. The main conclusion here is that when human beings flip coins, the outcome isn't random. Traditionally we have assumed that the outcome should be essentially random due to chaos theory - small differences in the initial conditions lead to large variations in how the coin behaves. This article shows that this doesn't lead to true randomness.

Yeah no shit, that's what I was implying. Nothing is truely random. Random cannot exist. Even things like the uncertainty principle only apply to human capability to measure, they do not extend to what actually is.

A toss is only random enough because we have no practical way to determine it before hand. That doesn't mean its not governed by strict laws

The bolded above depends on how you interpret quantum mechanics. The most widely accepted interpretation (the Copenhagen Interpretation) says that certain events in nature are intrinsically random and the universe is essentially non-deterministic. So far all of the evidence points this way (as opposed to a so-called Hidden Variable Interpretation).
 

Fox5

Diamond Member
Jan 31, 2005
5,957
7
81
(minor thread-jack)
Any thoughts on this?
Its claim:
This may well be the world's only discreet logic circuit to generate truly random output.

The 200Hz oscillator samples the phase noise of the 2MHz oscillator yielding a truly random coin-toss output.


It might become a side project eventually.
I've tried a few commercially-available LED candles, and I've found this:
Philips LED candles don't flicker. They blink. It's very obvious that it's nothing close to a candle.
Various other candles that come close to a flickering behavior seem to have a repeating pattern after a minute or so, similar to cheap white noise generators. Two of them side by side will eventually sync up, much like turn signals which are timed with different frequencies; at certain points in the cycle, they appear to nearly sync up.

I'm not sure exactly what's going on in that circuit, but I would think what'd you get is a continuously varying waveform that would eventually repeat. But I'm also assuming the oscillators reach steady state, if they are just sampling each other's noise before a stable waveform is created, then it could possibly be truly random (ish).
 

DT4K

Diamond Member
Jan 21, 2002
6,944
3
81
Originally posted by: moparacer
Funny this topic should come up this week.

I was at the drag races Saturday night and when you and your opponent want the same lane you have to flip a coin for lane choice. I never really give much thought to the whole coin flip process and while he was looking for a quarter I decided since I had called heads the last 3 times and won, I would call tails this time....

He flipped it, it came up heads, and I ended up losing the round.......

randomness fail

Did you think that the 4th flip would somehow be influenced by the first 3 flips?
 

PlasmaBomb

Lifer
Nov 19, 2004
11,636
2
81
Originally posted by: SunnyD
I've come to a science myself flipping coins. Using my technique, I can influence the outcome to about a 75% accuracy.

DrPizza >>>> joo
 

911paramedic

Diamond Member
Jan 7, 2002
9,448
1
76
Originally posted by: GodlessAstronomer
Originally posted by: JS80
lol shens that coin flip is 51%

Well you'd certainly know better than the researchers :roll:

Yeah, we all know they never skew any results to fit their theories... :confused:
 

sactoking

Diamond Member
Sep 24, 2007
7,648
2,925
136
Originally posted by: SunSamurai
Yeah no shit, that's what I was implying. Nothing is truely random. Random cannot exist. Even things like the uncertainty principle only apply to human capability to measure, they do not extend to what actually is.

A toss is only random enough because we have no practical way to determine it before hand. That doesn't mean its not governed by strict laws

What I find interesting is that the author dragged Taleb into this. If he had actually read Taleb he'd know that randomness is actually a matter of perspective. In a coin flip situation involving a flipper and an observer, the outcome may be predetermined from the flipper's view if he can always flip tails yet purely random from the observer's point of view if he has no method of knowing or determining the flipper's skill.

Even results such as this fall into an attribution error: an outcome not predicted occurred (51% result) and we, as humans, try to find an answer for it, like "skill", or "Human error", or "the side showing up has some advantage" when the real explanation is that the observed result could not have been predicted beforehand and any explanation after the fact is baseless and wrong.
 

DAPUNISHER

Super Moderator CPU Forum Mod and Elite Member
Super Moderator
Aug 22, 2001
32,056
32,580
146
All I know is, when we flip a coin over something, it has to hit the ground and bounce around. ;)
 

silverpig

Lifer
Jul 29, 2001
27,703
12
81
Originally posted by: Jeff7

I've also heard that a cheap way to create random noise is to take a CCD, enclose it in a completely dark, cold container, and boost its gain. The static generated would then be random, the product of electron vibration or motion, or some such thing.

That's called thermal noise.
 

sandorski

No Lifer
Oct 10, 1999
70,786
6,345
126
Originally posted by: mundane
Originally posted by: Arcadio
I knew that. That's why I use random.org every time I need a random event instead of a coin flip.

Okay, I'll bite. Why would you need a random number in your daily life?

Magic 8 Ball says..........Your Mom
 

tk149

Diamond Member
Apr 3, 2002
7,253
1
0
Originally posted by: SunSamurai
What the hell? Coins arnt separate from the laws of nature?

But... they are COINS.

My money violates the laws of physics. Outflow >> Inflow :(

Always knew about the 51%, but the fact that it's not the weight/density that affects the outcome is new to me.