• Guest, The rules for the P & N subforum have been updated to prohibit "ad hominem" or personal attacks against other posters. See the full details in the post "Politics and News Rules & Guidelines."

Probability - Tell me I'm not crazy

hypeMarked

Senior member
Apr 15, 2002
708
0
71
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
Oct 13, 1999
38,023
355
136
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
Dec 22, 2006
3,813
1
0
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
Oct 14, 1999
4,142
10
91
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
Apr 15, 2002
708
0
71
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?
 

thepd7

Diamond Member
Jan 2, 2005
9,429
0
0
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
Apr 15, 2002
708
0
71
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
Jan 2, 2005
9,429
0
0
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
Jan 12, 2004
20,139
1
0
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
Jan 2, 2005
9,429
0
0
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.
Thread reading for the win!
 

DLeRium

Lifer
Feb 19, 2001
20,158
20
81
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
 

esun

Platinum Member
Nov 12, 2001
2,214
0
0
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
Feb 24, 2005
7,797
1
0
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
Jan 19, 2006
900
0
71
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).
 

ASK THE COMMUNITY