Page 1 of 1

Fallacy

Posted: Sun Mar 20, 2011 4:49 pm
by Spyder
i read something somewhere once about this:

if you are offered a 1/3 chance for example, three upturned cups one has a ball hidden under it

you guess one time, and you dont find the ball, you had a 33.335% chance of getting it

if you change your mind after the first chance -- do you then get a 50% chance instead of 33.33%


im stuck from this point...

the odds dont actually change, but as you are given a choice does it matter?

Posted: Sun Mar 20, 2011 5:09 pm
by Matt Vinyl
I've posted about this on here before - it does work out and is far easier to understand if you vastly increase the numbers.

Say you have a 1000 pots and under 1 of them is the prize. You select one and then all the other pots are removed bar 2 - the one you selected and one other pot. If you swap to the other one, you have an excellent chance of it being under that pot as opposed to the one you initially chose.

It's the difference between 1/1000 and then 1/2 - the 'other' remaining pot has either been chosen at random by the person removing the pots or must contain the prize.

Not the best explanation, this may be clearer: Wiki Link - Monty Hall Problem

Posted: Sun Mar 20, 2011 5:22 pm
by Stevie S
It's called variable change.

Posted: Sun Mar 20, 2011 5:23 pm
by Stevie S
here is a quick and easy 2 minute talk!!

http://www.youtube.com/watch?v=6Rl_p3JlSd0

Posted: Sun Mar 20, 2011 7:14 pm
by deano8177
I might try this method I next play a DOND.