377:. It's been stated the article is wrong, but it's better to say it's ambiguous. No mention is made of whether the person will offer the same bet if another color shows. If the same bet is made irregardless of color (then modulo other possible ambiguities), then obviously the bet is not 50/50 as stated, since 2/3 of the time you will get a card with both sides the same color. This is similar to the "What are the odds that the other child is also a boy" question (or whatever that is called). That one is much more famous by the way, having been popularized by Martin Gardner, Marilyn Vos Savant, etc, with plenty of literature and references. --
225:. It's a nice example, but I'm afraid it's not encyclopaedic enough. I'm all in favour of short examples to explain key concepts, but this is a bit too long and more text book material. By the way, I didn't read and think it over carefully but it seems to me the conclusion is wrong. I think that if a card is chosen at random, and then either side is also chosen at random, and this side turns out to be green, then the probability of the chosen card to be the doubly-green one is 2/3, but the article says it's 1/2. --
566:. Yes I'm changing my vote again, too. Shows the process works. The version as of now, with input form several editors, has clear references, and we don't need to debate 1/2 versus 2/3 as editors. The references quoted are clear that the answer is 2/3. We are quoting their answer, not our opinions, per
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Thanks for the corrections. Must say I'm a little embarrassed that I made such an obvious mistake. When I saw the question and saw it was up for deletion I felt it would be a shame to lose such a nice example, at least I was right on that! By the way, I changed the colours from the original "white
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Ah, I think I see what you're saying now. In my previous response, I somehow assumed that when drawing a green/purple card, you would draaw it showing green. So your point is that when the host only offers the bet when green is shown, 2/3 of the time the other side is green. Well, ok. I withdraw
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Guess I was a bit too hasty. Having now actually read through it I have to say that I'm not convinced that it's quite correct :) The point of the example is that the scam artist can always offer you the same bet regardless of the colour of the card he flips up. But he'll offer you a win in the cases
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make a big difference. If for some reason, you don't believe me, you can try repeated trials yourself and see: draw a card out and then guess the opposite color shown. Do this, say, 25 times. Now try this again (same number of times) but always guess the same color as shown. Now finally, start
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original in any way, but I couldn't produce any references pertaining to the exact question. Any first-year text would do as reference for the rest. I thought this to be a good example because it illustrates so many fundamental and often overlooked points. Incidentally, I have attached a short
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Hmm Haukur suggests the artle (newly written) is now incorrect. Perhaps he is right. But this seems a discussion for the talk page, and helpful to get right. This seems a basis to improve and fix the article, and not a basis to delete. And meanwhile, I shall not bet my salary! Don't know who is
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as original research (not to mention wrong). Sorry, Heraclesprogeny, but I've read it through and I can't imagine that you found a reference that would make the claim "Thus, there are only two possible cards, double green-faced or purple/green-faced, and each has an equally likely probability of
107:. I've heard this before, it may be reasonably well known. I found one site which had a description of the puzzle and added the link to the article. But obviously it is no great tragedy if this is deleted since the article is quite short and doesn't establish context, source or notability. -
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This is a fairly standard example used in probability theory to demonstrate some fundamental concepts, like a riddle because of its relatively unintuitive results, but not quite a riddle. I have spend a couple of hours revising it and think it would make a great example in the section on
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Sure it does. If the host offers the bet only when one color shows, then it's 50/50, but if the host offers the bet always, then you should bet the other side is the same color. The situation is ambiguous precisely because we are not told the host's intentions. And the intentions
264:. Changing again as the article is still being edited and some clues to references have been found (see talk page). I still think that it is not encyclopaedic enough, but it's approaching the gray area so I don't feel comfortable deleting it while it is being worked on. --
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paragraph at the bottom of the article for those who still have questions about the answer. I will try to dig up some references soon, but understand if it must be deleted. Thank you for your patience as this is my first effort at contributing to this valuable resource.
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Now that
Heraclesprogeny has made a great article out of this we're of course keeping it somewhere :) Maybe somewhere on Wikibooks would ultimately be the best place? But if no-one can find the perfect home for it elsewhere then let's just keep it here. -
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If you weren't a mathematician I would just give up right now, but perhaps there is hope. Forget about the host. We draw from the hat a large number of times. True or false: of the draws when we see red, 2/3 of the time, the other side is red.
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Wow, this changes everything. Heraclesprogeny, I've only skimmed the new article, but it looks like great writing! Not encyclopedic style, but that might be fixable. Did you draw on any references for the article?
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You all make valid points. When writing, I was afraid it was lengthy and a bit too "text book", and I didn't include any refs. because, at the time of writing, I wasn't using any. This is all learnt material and
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over again but every time you draw a card and see purple, put it back in the hat, shake it up, and try it again until you see green. Then guess your color (it doesn't matter, since now it is even odds). --
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Uh, you mean green or purple, right? Your true false question shows that you're not getting the point of my comments - that it's important to state the host's intentions. This is quite standard fare.
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570:.Any editor with a different view will need to provide references to justify including this view. And yes there is an active talk on the discussion page - let's take "improving it" discussions there.
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our own mathematics around here. Ideally someone would come up with a reference, but pending that, it's all just original research. I feel justified in beating this dead horse not just because it's
161:: I don't see an obvious isomorphism to Monty Hall, although judging from the discussion Haukur found, the logical traps are similar. I considered a redirect, but it just seemed dishonest.
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What the host would have done if the other color had shown is an interesting thought experiment, but it doesn't affect the answer to the question, which is quite unambiguous.
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where the two-coloured card is the one selected. Since the odds are 2/3 that the card is actually single-coloured you only have a 1/3 chance of winning. I think :) -
319:, but because the current article is a cautionary example of what can happen when even well-meaning, intelligent, and thoughtful contributors ignore that policy.
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If you have a reference, by all means go nuts! I would love to see an article here. However, I suspect you'll have to start from scratch, no offense to anyone.
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Great improvement. Well done
Heraclesprogeny! Though the prose may be original, neither the question, nor the logic meet the meaning of original research.
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I couldn't decide whether to categorize this or nominate it for deletion, so I've done both. I guess it's, what... original research?
582:, as a vastly improved article. Similarly to the Monty Hall problem, 2/3 is correct. It seems illogical at first, but is true.
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Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a
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It would probably be classed under original research, but 'unoriginal riddle' would be more fitting.
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And who would have thought that this near-speediable little text dump would prove so fertile? :) -
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and red faces" because some people read much more into these things than they should. Cheers.
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The following discussion is an archived debate of the proposed deletion of the article below.
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being the one you chose". The whole point of the example is that this argument doesn't work.
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because it has no references, making it original research, as pointed out by
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I would agree with fixing the article, except that we are not in the business of
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now that the article has been vastly improved. The external links help too. -
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makes the right thing to do clear, whatever we all think of the new version.
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The above discussion is preserved as an archive of the debate.
77:- this is a riddle, not an encyclopedia entry. Seems to be the
503:, but not identical, and is in the probabilitic literature.
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Well, it was still quite the entrance! Happy editing!
39:). No further edits should be made to this page.
647:). No further edits should be made to this page.
445:I am intentionally asking a different question.
597:an excellent article and an asset to Knowledge
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622:based upon the upcoming improvements.
475:Um... something like that, yes. Sure!
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44:The result of the debate was keep.
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301:But I remain in the 'keep' camp.
361:. I'm sorry to change my vote.
18:Knowledge:Articles for deletion
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59:Three cards and a top hat
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94:. --
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331:not
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.