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# Statistics, Probabilities and Math Wizards...Explain this Please..

Discussion in 'The Okie Corral' started by Nalapombu, Oct 18, 2013.

1. ### NalapombuMillennium Member

3,098
203
Oct 21, 1999
Spring, TEXAS....USA
Hey all,

Something I have been thinking about today that I would like someone to explain to me. It involves gambling.

I was watching a show about casinos and how they operate and part of the show was about the roulette wheel. They showed the wheel and people betting and so on. Next to the wheel was a pole with a type of display on it that showed the last 15 or 20 numbers (with color)that came up. The guy they were interviewing said "see that pole right there, that little device has been a tremendous addition to the roulette area. It has made more money for this game than we could ever expect. People come up and see that the last 6 numbers that came up were BLACK and they plop down their cash and bet RED and they lose and lose. They can't understand that each turn of the wheel is a separate event." Not exactly what he said, but close.

Anyway, I thought how can that be? When you look at a coin flip if you were betting on the outcomes of that if you came up and seen that the last 6 times was HEADS, you'd bet on TAILS coming up next and you'd likely win. Wouldn't you?

There's an equal number of RED and BLACK spaces on the wheel, so why doesn't the same thing hold for the roulette wheel as it does with coin flips where there is a 50-50 chance of the outcome?

Thanks

Nalajr

27,216
9,150
Dec 18, 2004
San AntonioTexas
No. It really is that simple. No. future flips are not influenced in any way by a previous flip. NOT IN ANY WAY. Coins don't have a memory.

There is not a 50-50 chance. There are two green spots on the wheel.

Casinos make money on the vig. End of story.

Last edited: Oct 18, 2013

3. ### JerryVO

919
8
Oct 22, 2008
Tampa, FL
There are also 1 or 2 green spots on the wheel making the odds 48 / 52 in the casinos favor.

Most players don't play red or black only as the payoff is only 1 to 1 and frankly not that fun compared to the other bets paying anywhere from 2 to 1 to 38 to 1 giving the house even better odds.

Sent from my SCH-I605 using Ohub Campfire mobile app

Last edited: Oct 18, 2013
4. ### CourtCopMillennium Member

519
37
Feb 21, 1999
50/50 is 50/50. Doesn't matter if its the roulette wheel colors or the coin flip. Each spin or flip has the same 50/50 chance.

Sent from my ADR6350 using Ohub Campfire mobile app

5. ### CAcop

20,659
3,280
Jul 21, 2002
California
I think someone pointed out in an article recently that is not that uncommon to get 11 coin flips on the same side in a row.

I used to be able to figure it out but it has been 20 years since I had to know it.

6. ### NalapombuMillennium Member

3,098
203
Oct 21, 1999
Spring, TEXAS....USA
OK, for a minute lets eliminate the GREEN spaces on the wheel. That leaves an equal number of BLACK ans RED spaces, correct?

If you posted the numbers that came up in 500 spins of the wheel, and you discard the times it lands on GREEN, would the red and black results be 50-50 just like a coin flip? That ball on the wheel doesn't have a memory either.

Nalajr

Its not 500 spins in total. Its 500 single individual spins. Each spin is completely independent and no spin before or after has any affect on any one spin.

(apply coin flips to spins if you wish)

/

8. ### Riverkilt

Sometimes there are THREE green spots....greedy!

Remember when everyone thought that Keno had long odds? Now, with the lotteries Keno looks like a sure bet!

If I spin the wheel black 10x in a row whats the odds of the 11th spin being black = 50/50
red = 50/50

/

Last edited: Oct 18, 2013

27,216
9,150
Dec 18, 2004
San AntonioTexas
You are still unable to grasp one important fact. In this case, future events are not influenced by previous events.

If you do it a bajillion times, you will find, that no matter how many times a color comes up, the odds of the next event are still 50/50.

If red has come up 100 times in a row, you will find, if you do it a bajillion times, that the chances of red coming up again are 50/50. You will find an similar number of times it came up 100 and a similar number of times it came up 101.

People confuse that fact with the odds, before any events, of red coming up 100 times in a row.

11. ### Louisville GlockerUrban Redneck

2,290
27
Dec 17, 2010
Louisville, KY
The most likely ratio would be 50-50, but that doesn't guarantee it.

Think about flipping a coin. For the first flip, there is fifty percent chance heads, fifty percent tails. The next flip, there is fifty percent heads, fifty percent tails. How the coin landed the first toss has NO affect on how it lands the second toss. Sure it is most likely that it'll land once on heads, once on tails, but it is 25 percent likely to be two heads (half of a half, or one divided by two squared) and 25 percent likely to be two tails.

Knowing the first toss result doesn't help you figure out what the second toss will be. Both are independent events having fifty percent probability.

And sure there is only a 1/8 chance of three heads (a half times a half times a half, or 1 divided by 2 squared), but no matter the result of the first two tosses, the odds of the third being a head is still 1/2.

Probability is tricky, and it gets worse to calculate. It is what we use extensively in quantum mechanics, and what actuaries use.

12. ### F14ScottLuggageCLM

4,451
706
Sep 13, 2001
Katy, TX
The error most people make is that they confuse the "law of probability" with the "law of large numbers."

Probability says that a coin tossed will land on heads with a 50% chance, no matter what previous tosses occurred.

Large numbers says that, over time, heads and tails will average out to 50-50.

Confusing the two is called the Gambler's Fallacy: https://en.wikipedia.org/wiki/Gambler's_fallacy

13. ### mike0262pSpider

297
6
Aug 22, 2013
Tennessee
He is correct, Each spin is an individual and separate event of its own.

14. ### tsmo1066Happy Smiley

13,226
7,344
Aug 31, 2004
Houston, TX
Look at it like this. If you play Russian Roulette with one round loaded into a six shooter and you spin the cylinder, you have a 1-in-6 chance of blowing your brains out when you pull the trigger. Assuming you spin the cylinder again after each trigger pull, each time you pull the trigger you will have the same 1-in-6 chance of making a mess of your skull.

Now, let's say you have had a few drinks and you have played five rounds of Russian Roulette and you've managed not to kill yourself so far. Does that mean that the next time you spin the cylinder you are somehow destined to lose? No, because each spin of the cylinder is a stand-alone event and is in no way dependent on any of the previous spins. The five empty chambers don't somehow fill up with live cartridges just because you've managed to live through the first five spins.

18,182
1,881
Jan 20, 2004
Course, if you know how to play, roulette is one of the games you can make money on, repeatably.

16. ### ArtificialGrapeCLM

May 9, 2007
I saw Penn & Teller in Vegas years ago. Penn points out that all those lights outside on the strip are powered by 2 things: the Hoover Dam and bad math.

27,216
9,150
Dec 18, 2004
San AntonioTexas
You can win money at any casino game but it is not possible to sway the odds in your favor.

Jun 16, 2006
TEXAS

18,182
1,881
Jan 20, 2004