Can't Lose Coin-Flip Wager?

Factual Questions
21

This is easy, folks! The whole thing was given away when it was said that you don’t do the trick twice to the same crowd. Obviously, then, you change the RULES to meet the circumstances.

If the coin lands with the “called” face against the floor, you ask somebody to look at the face-up side. He’ll verify that it was indeed the wrong call.

If the coin lands with the “called” face up, you stoop over, pick it up, and show the BOTTOM face to everybody, saying, “As you can see, it landed HEADS [or TAILS]. So sorry!”

Who would be a big enough jerk to argue, “But that’s not how you play that game!” when there’s nothing at stake and it wasn’t their rules in the first place? In any case, if they complain, “It’s the side facing UP that’s the one you read,” you say, “Then why toss it on the FLOOR when I could simply catch it in my hand?” Who would continue debating from that point onwards?

But somebody might. So you then hand them the coin and say, “Okay, then, we’ll play by YOUR rules.” If they lose, THEY PAY FOR ALL THE FOOD. (Once again, you didn’t explain that whoever tosses, risks paying.)

If they spot that possibility, and ask, “Wait – if I toss it, do I pay?” You simply look at them like they’re an idiot and say, “Of course. I already went.” (It makes this sound like Russian Roulette.)

Anybody for a nice game of three-card monty? :slight_smile:

22

DropOfaHat, I meant to say this when you opened the thread, and I forgot.

Thank you for not reprinting the puzzle. I’m sure that Randi appreciates your efforts to protect his intellectual property (not to mention generating a few hits for him!), and I do too.

23

I think your first point about changing the rules is dead on, Tim. But I think Stan needs to confuse people’s memory of the premises (and “change” them after the fact, hopefully without anyone noticing), not come up with a new way the coin-flip game is played! I mean, claiming that the bottom face was the result… I don’t see how anyone could come away from that thinking that Stan was a good sport! And the rest of your scenario seems too complicated to be the right answer.

And while I don’t agree with Lanco Turbo’s suggested answer (calling it in the air is all it takes for the caller to be correct), I do agree with Lance that Stan stands to get pummelled for his trick, no matter how he does it!

24

“If you are wrong, I pay the whole tab!” he offers

This is a long shot, but perhaps if everyone was paying separately (separate checks), then offering to “pay the whole tab” might mean to simply pay his tab only. Just a thought.

25

DropOfAHat: “I think Stan needs to confuse people’s memory of the premises (and “change” them after the fact, hopefully without anyone noticing), not come up with a new way the coin-flip game is played! I mean, claiming that the bottom face was the result…”

I’m thinking that if Stan proceeds as I described it, and does it with complete confidence, people would be taken in or (and this is important) would appear to be taken in – similar to the way a stage hypnotist uses the good nature of participants to make them act hypnotized. I am sure that it is crucial to this trick that Stan has nothing to gain if he’s caught – which means that people would tend to be good-natured. If that wasn’t crucial, the trick would have been described as “If you people lose, you all have to cover the cost of my meal.”

It’s possible that Stan could come up with a way of describing the rules that is easy to reinterpret after the fact, but I’m guessing that the ultimate answer will be somewhat akin to a “force” (i.e. ensuring that people do what you want them to do while giving them the illusion of choice).

If there are any magicians here who follow the spirit of Penn and Teller, perhaps they could describe a simple “forcing” procedure, such as getting a person to pick the “right” card from a set of three. As I recall (I’m a bit vague on the details), the procedure is, in fact, not describable in only one or two sentences but requires a decision-tree, just as in my proposed solution to Stan’s problem.

I assume that the “real” answer will be published in next month’s column by Randi. Hopefully the person who wrote the OP will resurrect this thread to point us towards the solution.

[Hijack] Has anybody ever managed to listen to Randi’s radio show on WINZ’s Internet feed? I tried last week but it seems that he’s semi-permanently pre-empted by football. [/hijack]

26

I think we’re pretty much in agreement as to the basic theory of how Stan will approach the problem (i.e., he’ll make them think they freely chose something and that the outcome was random, when in reality they sort of did and it wasn’t); we just differ on how it will be carried out (you think he’ll claim the downward face was the desired result if the call doesn’t match the up-face; I think he’ll simply act as if a mismatch was the losing outcome).
I (being the thread-starter) will of course post Randi’s answer here on Monday, and we’ll see who’s closest (if we are even close, that is)!

27

DropOfAHat: I (being the thread-starter) will of course post Randi’s answer here on Monday, and we’ll see who’s closest (if we are even close, that is)!

If I’m right, you all have to buy me dinner. If I’m wrong, you have to pay for your own dinner.

28

If we’re both wrong, Randi buys us dinner. (And if one of us is right, he gets treated to dinner by Randi.)

29

There are simpler sucker-bets based on the coin toss. My favorite comes from Martin Gardner, and involves tossing a soda cracker. Yeah, a plain old saltine cracker. They do have a head and a tail, sorta. One side is always textured differently from the other.

How to do it:

Take 1 cracker. Show the sucker one side, declare it heads. Tell them, “if I toss the cracker and it lands on THIS side, you win.” Flip it over and say, “if it lands on THIS side, you win too.” Then hold the cracker standing up on its edge against the table, and say “if it lands on NEITHER side, I win.” Sucker agrees to bet. Take the cracker in one hand, crush it vigorously, and toss the crumbs into the air. You win.

30

Well, Randi has posted his answer. I must say, it is EXTREMELY disappointing (to my mind).

Remember my very first thoughts in the thread opener (two-headed or weighted coin), which I dismissed as being too obvious and simplistic? (Of course, when I dismissed them, the puzzle was set up wrong, and a trick coin would have made it very easy for Stan to win - in this version, it doesn’t help him all that much, so he has to have a second method of copping out, and it’s a doozy!) Not only does Randi invoke one of my rejected thoughts in his cop-out answer, but he has Stan do something completely ridiculous in mid-flip if the caller has guessed correctly! You’ll see, it’s unbelievable.

Timothy - remember when I said I thought your solution would never be considered “sporting”? Well, Randi’s answer is way WORSE - I would have been more satisfied with your solution…
So not only did Randi screw up the original presentation, but his answer is contrived and stupid. It’s a non-answer. I usually enjoy his puzzles - I hope this is an aberration (because he is travelling, and can’t devote his full attention to the website) and not a continuing trend. No new puzzle this week, so it’s hard to say…

Here’s the link - http://www.randi.org/jr/10-29-2000.html Scroll down almost to the bottom.

I guess it just goes to show I shouldn’t make ANY assumptions - like assuming that the puzzle would be intelligent and thought-provoking.

Sorry to be so bitter - I don’t mind being wrong, but if the answer is like this one, there was no way to be right.

31

I just realized, after some contemplation of Randi’s original setup, that his answer violates the given premises!!!
Either the premises were erroneous or they were violated by the solution. NOT because Stan used a two-headed coin - I figured that could be a possibility (in the incorrect version posted first, it would have been infallible!), I just couldn’t work out (in the second version) how he would deal with a mismatch - but because, based on the given premises, he cannot stop the coin in mid-flip.

Why? Because in the setup Randi says, and I quote: “…the designated guy calls it, the coin bounces onto the carpet. They all bend to see the result…” Only THEN does he stop the action: “Whoa! Time out.”

The way he has it set up, whatever Stan does/says is AFTER the coin falls to the ground! The setup doesn’t allow for him catching the coin in mid-flip, because we are told that the coin hits the floor!! If he had said “Stan flips the coin into he air, the designated guy calls it…” and stopped the action there, then certainly his solution would fit. But how are we to guess that the premises can be changed in this case but not for other puzzles?
I e-mailed Randi my compaint - I hope I don’t get a nasty reply!!

32

Dissapointing as a puzzle, but I can see the point that it was making. Stan never fails, but he aborts approximately half the time, so he only actually succeeds half the time. Sounds impressive if you don’t know all the details. Same thing with psychics if they can invalidate a test of their abilities after it has started. Their claims are as meaningful as the fact that Stan never pays for the whole meal.

33

Point taken about misrepresenting statistics - certainly Randi (if you’ve checked out some of his past articles) has shown how statistics can be bent (especially by people making supernatural claims) to produce misleading results.

But I STILL think that Randi went outside the boundaries allowed by the premises of the puzzle (i.e., it was a given that the coin hit the floor; now suddenly half the time he’s grabbing it BEFORE it ever hits the floor?). Poor, poor presentation of the puzzle…

34

I agree that Randi didn’t think this puzzle out very well. That makes three puzzles in a row that there was some ambiguity in the wording that made the puzzle unanswerable. Randi seems a little less than amazing these days.

35

The puzzles don’t really seem to be logic puzzles. They seem to be geared towards demonstrating how scam artists do their thing. A lot of times it’s not very logical at all. I dunno if I’d choose a puzzle format to make the point. Just pisses off readers.

36

I’m afraid this simply backs up what I’ve said before about the JREF site: it’s very badly put together.

For example, two weeks ago I wanted to find an article that describes why the $1,000,000 prize exists (for the benefit of some Believers), but all I could find on his site was an application form for the contest. There wasn’t a tidy little article explaining what it meant. Surely there should be a nice article on that subject for reference by journalists!

Getting back to the original topic, I see how Randi used the “puzzle” to demonstrate the idea of “aborting the test”, and that is indeed something I haven’t thought about much. After this little fiasco I’m not going to forget it!

Indeed, Randi himself “aborted” the test he proposed by changing the rules on us. Was that intentional irony, or just coincidence?

While I’ve got some Randi fans here (and I’m still one, despite the indifferently maintained web site), let me ask you something: is there “bad blood” between the people at CSICOP and the people at Skeptic Magazine? I’m aware there were some ruffled feathers during the Randi/Geller lawsuit, but are there people in the skeptic community who aren’t on speaking terms?

37

I have to agree I was disappointed with the puzzle. The original “incorrect” version was much more of a logic puzzle. The real solution certainly didn’t make him seem a “sport” to me. I did get the point Randi was making, but his method was irritating, to say the least. Of course the cons using those methods are irritating, too.

Timothy, Randi just announced that they are going to redo the site, and have a new person in charge of it. Maybe that will fix some of the complaints. Why don’t you send him an email with your comments. It could actually get implemented.

As for the CSICOP vs. Skeptic situation, there was a falling out some years ago over a certain incident regarding the Mars Effect. CSICOP conducted a study to attempt to refute the so-called Mars Effect, a twist on astrology. Their data was confusing and could be interpreted to support the effect, and that caused some bad feelings on how the situation was handled. CSICOP no longer performs tests. Randi is still involved, though doing his own thing, and Shermer is doing Skeptic, independent from CSICOP.