# Probability - Tell me I'm not crazy

#### hypeMarked

##### Senior member
Ok so I just had an argument with 2 of my buddies about probability. We were rolling dice and this talk comes up. They say if a face of a dice has a probability of 1/6, then if you roll 6 times, you will get what you want. I say, that is not necessarily true and that it's not how probability works. Then they start to flame me about statistics and crap like that. I remain calm and try not to hurt them, but I can't believe what the hell they are smoking. We're like > 20 years old.

#### Viper GTS

##### Lifer
No particular outcome is guaranteed, if that is what they are trying to imply.

Granted as the number of rolls goes up the odds of it NOT appearing approach 0 but there is no guarantee to see any particular number in any particular number of rolls.

Viper GTS

#### tasmanian

##### Diamond Member
Your not crazy, if you said theres a chance the dice wont land on say 4 if you roll it 6 times.

#### Kyle

##### Diamond Member
So they think that if they roll a 6 sided dice 6 times, then, lets say a 3, will ALWAYS come up at least once? wow. You should go get a dice and prove them wrong...

*edit*
so with that logic- they are saying that there is no way that a single number will be rolled twice w/in 6 rolls...

I'm half drunk and this seems stupid to me....

#### hypeMarked

##### Senior member
I'm saying that there's a chance that even after 6 rolls you won't get the number that you want. They say it's not true and are standing firm. I know this is a rant, but damn, how can people be like this?

#### mooglemania85

##### Diamond Member
Sorry, but your friends are friggin idiots.

#### thepd7

##### Diamond Member
Originally posted by: hypeMarked
Ok so I just had an argument with 2 of my buddies about probability. We were rolling dice and this talk comes up. They say if a face of a dice has a probability of 1/6, then if you roll 6 times, you will get what you want. I say, that is not necessarily true and that it's not how probability works. Then they start to flame me about statistics and crap like that. I remain calm and try not to hurt them, but I can't believe what the hell they are smoking. We're like > 20 years old.
Not how it works.

How it works: They are Independent events and you have to work the converse.

The probability of NOT throwing a particular number in 6 throws = (5/6)^6 = .335, or 33.5%. The probability of throwing a particular number in 6 tries is 1-.335 = .665, or 66.5%.

If they think they are right ask them to bet and give you 4:1 odds or better. Then clean house. You will win 40% of the time and when you win you will make 4x what you bet, that would be nice.

edit: start the betting high: unless they are REALLY REALLY stupid they will quickly realize you are kicking their ass. So say, hey I have my \$20 against your \$80 that I WON'T roll a 1 in the next 6 dice rolls.

It would actually be better for you if you DO rolla 1 the first time or two so you could keep them on the hook longer. I forsee money in your future.

#### hypeMarked

##### Senior member
Thank you all so much

#### thepd7

##### Diamond Member
Originally posted by: hypeMarked
Thank you all so much
yw, my cut is a very reasonable 10% of profit.

#### hypeMarked

##### Senior member
Hahaha...will do I just can't believe what I hear coming out of their mouth....My respect for them just got lowered.

#### thepd7

##### Diamond Member
Originally posted by: hypeMarked
Hahaha...will do I just can't believe what I hear coming out of their mouth....My respect for them just got lowered.
Are they drunk, stupid, or both?

#### chuckywang

##### Lifer
Originally posted by: hypeMarked
Ok so I just had an argument with 2 of my buddies about probability. We were rolling dice and this talk comes up. They say if a face of a dice has a probability of 1/6, then if you roll 6 times, you will get what you want. I say, that is not necessarily true and that it's not how probability works. Then they start to flame me about statistics and crap like that. I remain calm and try not to hurt them, but I can't believe what the hell they are smoking. We're like > 20 years old.
If you're looking for, say, a 1 during six dice rolls, the probability you'll hit it is: 1-(5/6)^6 = 66.5%.

So in conclusion, you're right: it's not necessarily true.

#### thepd7

##### Diamond Member
Originally posted by: chuckywang
Originally posted by: hypeMarked
Ok so I just had an argument with 2 of my buddies about probability. We were rolling dice and this talk comes up. They say if a face of a dice has a probability of 1/6, then if you roll 6 times, you will get what you want. I say, that is not necessarily true and that it's not how probability works. Then they start to flame me about statistics and crap like that. I remain calm and try not to hurt them, but I can't believe what the hell they are smoking. We're like > 20 years old.
If you're looking for, say, a 1 during six dice rolls, the probability you'll hit it is: 1-(5/6)^6 = 66.5%.

So in conclusion, you're right: it's not necessarily true.

#### UncleWai

##### Diamond Member
I think you guys should just make love and less fighting.

#### Suspicious-Teach8788

##### Lifer
Originally posted by: thepd7
Originally posted by: hypeMarked
Ok so I just had an argument with 2 of my buddies about probability. We were rolling dice and this talk comes up. They say if a face of a dice has a probability of 1/6, then if you roll 6 times, you will get what you want. I say, that is not necessarily true and that it's not how probability works. Then they start to flame me about statistics and crap like that. I remain calm and try not to hurt them, but I can't believe what the hell they are smoking. We're like > 20 years old.
Not how it works.

How it works: They are Independent events and you have to work the converse.

The probability of NOT throwing a particular number in 6 throws = (5/6)^6 = .335, or 33.5%. The probability of throwing a particular number in 6 tries is 1-.335 = .665, or 66.5%.

If they think they are right ask them to bet and give you 4:1 odds or better. Then clean house. You will win 40% of the time and when you win you will make 4x what you bet, that would be nice.

edit: start the betting high: unless they are REALLY REALLY stupid they will quickly realize you are kicking their ass. So say, hey I have my \$20 against your \$80 that I WON'T roll a 1 in the next 6 dice rolls.

It would actually be better for you if you DO rolla 1 the first time or two so you could keep them on the hook longer. I forsee money in your future.
Well if you bet like that you need to bet a few times just in case things don't go well. It's a long run thing just like pot odds in poker =P

#### TallBill

##### Lifer
Your friends are morons. Drop them, now.

#### FoBoT

##### No Lifer
Originally posted by: mooglemania85
Sorry, but your friends are friggin idiots.
:thumbsup:

#### electronicmaji

##### Banned
maybe they just really really suck at math??

#### FleshLight

##### Diamond Member
I think they are correct.

E = nP = (6)(1/6)=1

#### DangerAardvark

##### Diamond Member
Originally posted by: electronicmaji
maybe they just really really suck at math??
They just suck at thinking in general.

#### chuckywang

##### Lifer
Originally posted by: FleshLight
I think they are correct.

E = nP = (6)(1/6)=1
And I think you have no idea what you're talking about.

#### esun

##### Platinum Member
Originally posted by: FleshLight
I think they are correct.

E = nP = (6)(1/6)=1
Expected values of random variables are never "guaranteed" to happen. Sure, I would expect on average to get a particular value in 6 rolls, but I'm never guaranteed that behavior.

#### ForumMaster

##### Diamond Member
well it's independent events. they don't affect the probability of the next throw. each throw, there is the same 1.6 chance to get any number. it's not impossible to get all sixes or anything like that.

#### Manuwell

##### Senior member
I suck at probability but I guess that, as Forum master said, one throw does not influence the next one. You have 1/6 of possibilities for each value at every attempt, then you reset it all and start again.

So yes, you are right and your buddies suck at logic (more than I do).

#### Rangoric

##### Senior member
Originally posted by: FleshLight
I think they are correct.

E = nP = (6)(1/6)=1
Thats the Gambler's Folly, not the actual probability.