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RogerTheShrubber Veteran user 301 Posts 
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On Oct 30, 2015, R2D2 wrote: Yes. With no cards between them. |
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RogerTheShrubber Veteran user 301 Posts
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On Oct 30, 2015, alecStephenson wrote: I like the book too (although I could do without all the silly "Freddy" crap), but one thing I noticed is that he gives the odds on almost everything in the book except for this, leaving me of course no less confused than I was when I started reading it. I had heard of the "two cards" thing from my aunt years ago, back when the Monkees were regularly on the charts, and when I saw this section of the bookmy hopes shot through the roof because he was giving odds on almost everything else. No such luck. |
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RogerTheShrubber Veteran user 301 Posts
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On Oct 30, 2015, alecStephenson wrote: All reasonable guesses, but actually none are on the mark. By "lightning fast" I mean I move the cards from my left hand to my right as if I were examining a gin rummy hand for the first time instead of actually dealing out every card and flipping them over, and while I'm no cardistry wizard I certainly wouldn't miss a card between my target cards even once, much less enough times to warp the results as much as I've seemed to. My vision sucks, but it isn't THAT bad. I always riffle shuffle several times and never use the same values on consecutive hands. In fact, I brought my kids into this and had them do the trials, even paid them to do so. My wife has pitched in, too. Not once has anyone scored less than 63/100. So you can see why I'm even more confused what with being shown math that runs so rampantly counter to my results but looks so solid at the same time. |
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R2D2 Veteran user 304 Posts
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Ok, I can't explain any of this. It looks like I understood the original problem correctly, so I can't understand how your kids got different results.
How many trials did they do? (I'm reaching here.) |
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RiderBacks Loyal user 251 Posts
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I'm provisionally convinced by R2D2's explanation and answer of 48.6%. That said, I would expect that in the real-world, the percentage would be higher. If we ask John Q. Public to pick up his deck and name two values, we can expect him to pick up a deck which isn't shuffled well. It's probably left over from his last poker game. And if we ask him to shuffle, he isn't going to give it a faro or two either. He's going to overhand or riffle it once or twice in a fairly lame fashion.
If he plays poker, I bet if we looked through his deck before he shuffled, we'd find lots of standard pairs, probably often involving face cards (say from last night's poker game's full house). Most of the face cards top the list of "verbal accessibility" with the AS being at the very top of the list. So if on the spot and asked to name two values, we expect a lot will opt for the most verbally accessible cards (which, I suspect, are more likely to be next to one another in most people's decks.) Considerations such as this could push the real-world percentage much higher than the theoretically computed percentage (which isn't good). That's a potential partial explanation for the difference between theory and practice. |
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Terrible Wizard Inner circle 1973 Posts
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That makes some sense.
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RogerTheShrubber Veteran user 301 Posts
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R2D2, the household results are as follows as of this writing:
Me: 558/700 Wife: 139/200 Oldest heir: 221/300 Second oldest heir: 152/200 Second youngest heir: 293/400 Youngest heir: 68/100 What puzzles me most about this is that no matter how solid the math is, it seems unthinkable that Lovell could be so far off given how much he knows about odds and how many odds he includes in other sections of the book. He didn't have the exact numbers when I wrote him, but he said it was roughly 75% and that's about what we're seeing in Shrubbery Central. |
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Terrible Wizard Inner circle 1973 Posts
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Weird .... This is intriguing.
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RogerTheShrubber Veteran user 301 Posts
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On Nov 4, 2015, Terrible Wizard wrote: My thoughts exactly. And while Riderbacks' post is logical, I've already addressed the shuffling question. Further, instructions given to the family is to never use the same two values together in any one trial run. |
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R2D2 Veteran user 304 Posts
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On Nov 4, 2015, RogerTheShrubber wrote: Wait, what do you mean by that? So if you pick 6 and 8 for the first trial then you might pick 2 and 9 for the next trial but not 6 and 8 again? And for each trial, you shuffle, then pick two ranks (before looking at the cards) and then go through the deck? Let's say you pick 6 and 8. If you see a 6 followed by another 6 does that count as a success? Or do you need to see a 6 next to an 8? |
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RogerTheShrubber Veteran user 301 Posts
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On Nov 4, 2015, R2D2 wrote: In order: 1.) Yes, you wouldn't pick a 6 and 8 again during a series of trials, at least not together. I instructed the family to make it as varied as possible, so you might see an order like this: K-6, then 4-2, then 7-J, then Q-3, then 5-9, and so on. I don't tell them what to pick, I only tell them how, and told them not to do anything that would use either of the same values in a previous run in the next one. So no A-2, then A-3, then A-4 and so on. Eventually if you do enough trials you have to repeat somewhere, but I mix it up and have the family do the same. 2.) Yes, shuffle, pick two ranks you haven't yet used together without looking at the deck. 3.) No, a 6 followed by a 6 would not be a success. Any 6 next to any 8 in either order with no card(s) between them would. If during a single trial you have two or more instances of a 6 being next to an 8, though, it only counts once (and in fact once I see one, I stop and go to the next trial, which now that I think of it I wish I hadn't been doing, it would have been interesting to see how often I got multiple successes in the same run through a deck). |
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R2D2 Veteran user 304 Posts
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Ok, you're doing everything right! I can't explain this.
Does someone else want to try? 
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Terrible Wizard Inner circle 1973 Posts
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Anyone know any math professors with an interest in magic
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R2D2 Veteran user 304 Posts
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I still can't get over the fact that RTS got his family to participate *hundreds* of times! I wonder if RTS and I should Skype each other so I can watch him do a trial and vice versa so we can see if we're doing anything different.
Maybe I should try it first with regular cards. Incidentally, has anyone asked Simon L himself? |
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RogerTheShrubber Veteran user 301 Posts
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On Nov 4, 2015, R2D2 wrote: Don't give my family too much credit here. In order to get them in on this, I have to pay the kids and barter with the wife (take some of her turns with household chores). As I said earlier, I wrote to Simon some time ago and asked him about it. Earlier in the thread I said he answered with an approximate figure of 75%, but I just dug up the email and it seems that he actually said 7/10. The email was from January of 2013 and the exchange reads as follows: Dear Mr. Lovell, I must ask (this is a question that's haunted me for years) the following: In one segment you explain a bet which in a different form you use as a card trick over the radio. You tell someone to pick two denominations at random (king and three, five and nine, etc) and shuffle the deck, and the odds say that two cards of those denominations will be found together. My aunt taught me the same thing when I was a child and for years I've wondered what the exact odds are. Math teachers in school either didn't know or thought I was trying to pull some hustle on other students and refused to tell me. Since that level of math was never my strong suit, I'm honestly unable to do it myself. Do you know what the odds are and how they're arrived at? Many thanks in advance for any answer you might give. Loved your book. My father is hooked on it too. Regards from Alexandria, VA - Roger R***** RE: From your book, How to Cheat at Everything Hi Roger, Like yourself I was taught the effect many years ago as a very young man (in my case from a hustler pal of my grandfather) and have used it ever since. I've never bothered working out the exact odds and have just been happy that it works a lot of the time. I would, at a rough guess, from numerous performances of it, say that the the percentagess are around 7 out of 10 in my favor. That's just a guesstimation though! Glad you like the book! Kind regards, Simon simon@***********.com |
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RiderBacks Loyal user 251 Posts
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May I ask what kind of shuffle you are having the fam use and, if it's a riffle shuffle, how many times you have them riffle shuffle between tries?
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RogerTheShrubber Veteran user 301 Posts
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On Nov 5, 2015, RiderBacks wrote: Sure. I haven't been overly specific with them on the riffle shuffle (that's what we all use). I'm in the habit of seven riffle shuffles between pretty much anything (deals in a game, deals for these trials, etc), but I told them to shuffle them well and then trusted them to do that (it should be noted before anyone asks that I don't supervise them or watch them when they do this, nor did I tell them what numbers could be expected). And again, I did tell them not to use the same values on consecutive deals, so I really don't think shuffles (good or bad) are having a big effect here, but as with anything else, I could be wrong. |
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R2D2 Veteran user 304 Posts
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Btw, if anyone wants to see a simple spreadsheet simulation of this, send me a PM and I can "share" it over google docs. Google's version of Excel isn't super-fast but you can manage a sheet with 1000 sims and it's not *too* slow. 1000 sims isn't great as far as "margins of error" go, but you can hit delete in an empty cell to reset the random numbers and see a new sim. The percentage of successes indeed hovers around the high 40s and you hardly ever see it go into the high 50s. More than 1000 sims would make the whole sheet unmanageable.
RTS, you might want to take a look (if you're spreadsheet-savvy) and tell me if it matches what you're doing. |
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carlyle Regular user 166 Posts
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Interesting thread and a fairly addictive experiment. I tried it with my wife 35 times and came out 18 times correct, 17 times wrong. We shuffled between us and varied the shuffles, the cards were always well mixed. Sometimes she'd choose the pair, sometimes I would, sometimes she'd say a value and I'd suggest the second value.
I found that it was never correct more than 3 times in a row (and that only once), I wonder about that kind of thing by the others. I'm not a betting man, but it's pretty magical when it does happen. |
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RogerTheShrubber Veteran user 301 Posts
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On Nov 6, 2015, R2D2 wrote: I'm probably not as spreadsheet savvy as you are, but I'd LOVE to take a look. PM coming. |
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Posted: Oct 31, 2015 11:37 pm 