Subject:
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Re: math question (or pattern... whatever...)
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Newsgroups:
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lugnet.off-topic.geek
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Date:
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Wed, 5 Mar 2003 03:16:45 GMT
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Viewed:
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501 times
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In lugnet.off-topic.geek, David Koudys writes:
> In lugnet.off-topic.geek, James Brown writes:
> > In lugnet.off-topic.geek, James Brown writes:
> >
> > > No, because you only tried to remove r2. We are only removing *a* red ball
> > > from the bag; because there are 2 red balls, and only 1 is ever in our hand,
> > > there is always a red ball in the bag to remove. It is irrelevant whether
> > > that ball is r1 or r2.
> > >
> > > Redoing it with numbers:
> > >
> > > hand bag
> > > r1 r2 w
> > > r2 r1 w
> > > w r1 r2
> > >
> > > Now removing a red ball from the bag we get:
> > >
> > > hand bag
> > > r1 w (r2 is the only red ball, it is removed)
> > > r2 w (r2 is the only red ball, it is removed)
> >
> > Bleargh! typo.
> > r2 w (r1 is the only red ball, it is removed)
> >
> > > w r1 OR r2 (either may be removed, as both are in the bag)
> > >
> > > James
>
> Saw that ;) but understood...
>
> but if we're talking one instance--one event--and that's what we're, indeed,
> talking about--you are on a game show, one event--you have one chance of
> winning one car behind one door....
>
> so you have 3 doors
>
> I won't bother to number them...
>
> you choose one of those doors--you have a 1 in 3 chance of picking the right
> one.
Ok, here's where I'll take it from. The car is behind one of the doors, so
the probabilities must add up to 1. 3 doors, 1/3 of a chance for each door.
You pick door 1. There is a 1 in 3 chance the car is behind that door.
There is a 2 in 3 chance that the car is behind one of the other doors.
Follow me?
Now, here's the thing - ** those probabilities DO NOT CHANGE. ** The odds
of your door being correct are still (and always) 1 in 3.
If at this point you were offered "you can stick with what you've got, or
you can have the other two doors?" what you would take? The other two doors
- that's a 2/3 probability of having your car.
Revealing one of those two doors as a goat changes nothing - We already know
that one of those two doors has a goat behind it! Revealing what's actually
behind doors at this point is an academic excercise; the probabilities have
already been determined.
James
(gah. I can't believe I'm still arguing this.)
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Message has 1 Reply:
 | | Re: math question (or pattern... whatever...)
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| (...) Didn't mean to offend. Sorry 'bout that. I read the site thru again and your synopsis of the explanation above and I concur that it should be 2/3, but I like to work things thru... :) If I were to walk in off the street right after one of the (...) (22 years ago, 5-Mar-03, to lugnet.off-topic.geek)
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Message is in Reply To:
| | Re: math question (or pattern... whatever...)
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| (...) Saw that ;) but understood... but if we're talking one instance--one event--and that's what we're, indeed, talking about--you are on a game show, one event--you have one chance of winning one car behind one door.... so you have 3 doors I won't (...) (22 years ago, 5-Mar-03, to lugnet.off-topic.geek)
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