Think you know probability?

This is a discussion on Think you know probability? within the General Trading Chat forums, part of the Reception category; I'm sure some of you have heard this one before, but for those who haven't, give me your answers: You ...

View Poll Results: What do you do?
Spin the cylinder again, then fire 32 60.38%
Just pull the trigger 21 39.62%
Voters: 53. You may not vote on this poll

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Old Feb 14, 2009, 5:32pm   #1
 
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Think you know probability?

I'm sure some of you have heard this one before, but for those who haven't, give me your answers:

You are handed a revolver, with two bullets placed in adjacent chambers in the 6-chamber cylinder. The cylinder is spun to a random position and the loaded gun is handed to you. You put the barrel to your head and pull the trigger - an empty click.

Now, you are told that you must pull the trigger one more time. Do you re-spin the cylinder, or just pull the trigger again?

NB. Please do not post explanations for your answer until everyone has had a chance to make up their mind. Also don't bother Googling an answer, it kind of defeats the purpose of the exercise.

Hint: Read the initial conditions carefully, and visualise the situation.
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Old Feb 14, 2009, 5:37pm   #2
 
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Quote:
Originally Posted by Skill Leverage View Post
I'm sure some of you have heard this one before, but for those who haven't, give me your answers:

You are handed a revolver, with two bullets placed in adjacent chambers in the 6-chamber cylinder. The cylinder is spun to a random position and the loaded gun is handed to you. You put the barrel to your head and pull the trigger - an empty click.

Now, you are told that you must pull the trigger one more time. Do you re-spin the cylinder, or just pull the trigger again?

NB. Please do not post explanations for your answer until everyone has had a chance to make up their mind. Also don't bother Googling an answer, it kind of defeats the purpose of the exercise.

Hint: Read the initial conditions carefully, and visualise the situation.
Its obvious - give spanish a call see what he recommends then do the opposite.
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Old Feb 14, 2009, 6:18pm   #3
 
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Skill Leverage started this thread Do you laugh at all your own jokes in real life, or just on internet forums
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Old Feb 14, 2009, 6:23pm   #4
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Where is BSD, these days? I hope he's not into cross-dressing.
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Old Feb 14, 2009, 6:30pm   #5
 
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Excellent, Monty Hall tooled up. Do we need to account for the weight of the bullets or can we assume each chamber has a 1/6 chance of selection? I've actually no idea how revolvers work in this respect. Regardless, it's going to be the second choice.
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Old Feb 14, 2009, 6:39pm   #6
 
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Easy!
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Old Feb 14, 2009, 6:41pm   #7
 
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Originally Posted by Paul71 View Post
Where is BSD, these days? I hope he's not into cross-dressing.
He pulled the trigger again with out respinning.
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Old Feb 14, 2009, 6:46pm   #8
 
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It depends if you want to improve your chance of survival, or if you fancy topping yourself !

After spending an afternoon reading T2W I'd be definately inclined to re spin the cylinder , but its truly great threads such as this that get you thinking, so with my faith in humanity temporarily restored, I'll pull the trigger.
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Old Feb 14, 2009, 6:47pm   #9
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Originally Posted by frugi View Post
Excellent, Monty Hall tooled up. Do we need to account for the weight of the bullets or can we assume each chamber has a 1/6 chance of selection? I've actually no idea how revolvers work in this respect. Regardless, it's going to be the second choice.


It doesn't matter, frugi. What matters is wether or not it's a game, or just a maths question.

Who in the right mind is going to hand you a loaded gun and ask you to blow your own brains out?

Why not do it themselves?

It's a lot safer for you to kill them,....."...no Mr. Bond, i excpect you to die..."




Know what i mean?
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Old Feb 14, 2009, 6:52pm   #10
 
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Quote:
Originally Posted by Skill Leverage View Post
I'm sure some of you have heard this one before, but for those who haven't, give me your answers:

You are handed a revolver, with two bullets placed in adjacent chambers in the 6-chamber cylinder. The cylinder is spun to a random position and the loaded gun is handed to you. You put the barrel to your head and pull the trigger - an empty click.

Now, you are told that you must pull the trigger one more time. Do you re-spin the cylinder, or just pull the trigger again?

NB. Please do not post explanations for your answer until everyone has had a chance to make up their mind. Also don't bother Googling an answer, it kind of defeats the purpose of the exercise.

Hint: Read the initial conditions carefully, and visualise the situation.
If you re-spin does it have to be a random spin?
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Old Feb 14, 2009, 6:52pm   #11
 
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Admittedly my reflex was "this is [well-known probability problem], I'll change it please", but thinking it through properly, I would pull the trigger without a respin.
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Last edited by fifty2aces; Feb 14, 2009 at 7:22pm. Reason: removed potential clue
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Old Feb 14, 2009, 6:55pm   #12
 
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I would pull the rtigger again!!
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Old Feb 14, 2009, 6:58pm   #13
 
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ive got a differnt awsner. the odds are the ****ing same!
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Old Feb 14, 2009, 7:01pm   #14
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Originally Posted by Genics View Post
ive got a differnt awsner. the odds are the ****ing same!



For some, 50-50, and spinning the chamber is all they have.
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Old Feb 14, 2009, 7:01pm   #15
 
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Skill Leverage started this thread So much for not discussing it then...!

Fifty2Aces is spot on. At the time of posting this it was a dead 50/50 split between those who got it right and those who got it wrong.

Fifty I'd appreciate it if you (or anyone else who got it right) gave people a little time to think it out before explaining
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