Are all dice loaded?

Question

Many dice use small dimples to indicate numbers. Doesn't this introduce a small bias? For example, wouldn't this make the side with 6 lighter than the side with 1, so you would expect 6 to come up more often than 1.

Does this mean that all dice are loaded? If so, how much bias does this introduce?

Admittedly, the bias is small, but it might make a difference at a large casino.

I appreciate that all dice have some imperfections, but such imperfections would introduce random bias. The dimples, however, might introduce a systematic and predictable bias, a bias that it might be possible to exploit.

Answer 1

Casino dice pips are filled in after they are drilled, and the stuff they fill in the pips with are the same density as the stuff used to make the die, so this wouldn't cause a problem.

I guess though the pips might make a difference with, say, Monopoly dice, but in truth the bias caused by pips would be greatly overshadowed by face size. Most dice aren't perfect cubes and so two of the sides will be slightly bigger then the others, say, the 2 and the 5. This can be caused through manufacturing defects (casino dice won't have this much because they cost more), and through repeated use. Casino dice are only used for like 8 hours then they are sold at game stores and such.

Answer 2

This may explain why the sides of a die are arranged as they are. Notice how the 6 is always opposite from the 1, the 2 is opposite from the 5, and the 3 opposite from the 4. So that balances out the dimples, since in each case they add up to 7.

Also, look closely at the die and you'll see that the dimple on the 1 side is slightly larger than the dimples on the 6 side. (Sometimes this difference is more pronounced)

Answer 3

I read about this once, and I wish I could remember where so I could share the source with you, but I recall the reason dice used in casinos were changed to have the pips be decals of spots rather than dimples was because of the very same (albeit very small) bias about which you ask.

With 1's heavier than 6's, 2's heavier than 5's, and 3's heavier than 4's, dice rolls with greater sums did appear by experimentation more often than rolls with lower sums, though if I remember correctly, the difference was by less than a tenth of a percent.

Answer 4

I've always wondered about this exact same question and my lack of an answer is why I'm still wondering. I'm sure it does, although it's bound to very tiny,and figuring out how to measure it is beyond my ability. I'm very happy that I realize that now, or
I'd probably spend the next six months trying to figure it out. (I get that way sometimes with a good mathematical challenge)

I would expect that casino operators have probably done studies to determine exactly to what extent is affects the dice and if it were even negligible, they'ed adjust their odds accordingly. They're not there to give away one penny more than they have to.

Even dice manufactured as precisely as possible with no markings at all are bound to have a slight bias to one side or another due to microscopic or atomic level variations smaller than the finest manufaturing standards can control.

Answer 5

Good question! I hadn't really considered it, but it does seem logical. I imagine whatever bias it introduces it minimal, otherwise someone would have noticed by now and tried to exploit it, heh. I guess next time you are gambling for big money, go for the 6!

Answer 6

Every dice is loaded to some degree, and not just because of the numbers although that is a good reason as well. Dice can only be made to be weight reliable to a degree of accuracy. This degree of accuracy is really good, as good as they can make it, but it isn't perfect, just like you cannot make ANYTHING exact, only close enough for practical purposes.


Tiger Striped Dog MD

Answer 7

I have no idea

Answer 8

NO