Ask The Wizard #211
Is the "parity hedge" myth in craps true?
No. I had to Google this to find out what this is. This appears to me to be an amusing urban legend about some young scientists who developed a winning craps system. The story is told at Quatloos. I would file this under other fictional stories that have become mistaken for fact, like Joshua’s missing day. As I have said hundreds of times, not only can betting systems not beat games like craps, they can’t even dent the house edge.
Playing in a poker league one night and this came up. Blinds were $300/$600 and the first to act bet $2,000 and then the next two folded when it was my turn. Not seeing the original bet, I bet $3,000 without saying raise or call since I thought I was the first to bet. I started to pull back $1,000 and call but was told that my chips had to stay in and that I would have to put in another $1,000 to raise the first bet or just flat out muck my hand. Could you please give me the proper ruling on this situation. Thank you.
I think neither of you is right. It is correct that when you put in more than $2,000, you were implying you were raising the pot. The minimum raise should have been $1,400, for a total bet of $3,400, contrary to the table ruling. This is because the last bet of $2,000 was a $600 call and $1,400 raise. Your bet was only a $1,000 raise. So, you needed to put in another $400, or muck your hand. (source)
At BetJamaica I played 30 hands and lost 21.5 units. What is the probability of that?
The standard deviation per hand in blackjack is 1.15 under Vegas Strip rules (source). This can vary, depending on the rules, but since you didn’t state them, we’ll go with 1.15. So, the standard deviation of 30 hands would be sqrt(30) × 1.15 = 6.30. I don’t know what their blackjack rules are, but let’s assume a house edge of 0.4%. So in 30 bets, you would expect to lose 30 × 0.004 = 0.12 units. Your losses exceeded expectations by 21.5-0.12 = 21.38 units. That is 21.38/6.3 = 3.39 standard deviations south of expectations. The probability of that is 0.000349, or 1 in 2862. I’m afraid this doesn’t rise to the level to make any kind of accusations. If you still suspect something fishy, I would gather a larger sample size.
I have a friend who was part of a casino staff who watched over roulette tables, and he told me that when people start to win the casino changes the croupier. I have also seen a member of the staff ask a croupier to spin the roulette wheel at a different speed. Doesn’t this mean that the casinos are certain that the croupier can cause a non random series of numbers to appear? Doesn’t this mean that a gambler can look for a "lucky" table where the croupier doing regular spins gives them a better chance of winning?
Sadly, ignorance can go pretty high up the ladder. I don’t dispute that an expert can clock the wheel on a very slow spin. However, that issue aside, changing dealers does not change the odds. There is no such thing as a lucky or an unlucky dealer. Superstition is a difficult thing to let go of. As I have said many times, the more ridiculous a belief is, the more tenaciously it tends to be held.
First, love the site, very informative! Background: When using a Random Number Generator (RNG) to determine certain payouts for a finite set, such as 1 million lottery scratch off cards, the RNG can be programmed to drop non-pay or add pay selections so as to keep a more even distribution of winners throughout the finite set of cards created. The goal is to maintain a more even distribution in the cards along with the payout percentage as required. Is this, or can this programming be done in Nevada? The law of averages would indicate no need for this, but is it not theoretically possible for a signed 97% slot machine to payout 95% one year and 99% the next year unless some control on the RNG was made?
Thanks for the kind words. Scratch cards and pull tabs can indeed be printed in batches. These batches will have a specified number for each win, and the return of the overall batch will be exactly as the maker intended. In some jurisdictions, where only pull tabs are legal, the outcome can be displayed to the player on a video monitor, in the form of a slot or video poker machine. However, in Nevada, that is not how slots work. Each play is completely independent of the past. A machine programmed to average a 97% return, could indeed pay under 95% or over 99% over a year, especially if not heavily played.