Re: Those d### strange dices?

>I regularly play Role-Playing-Games.
>There are dice involved
>A D4 (a 4-sided die)
>A D6 (The "normal die")
>A D8 (a 8-sided die)
>A d12 (a 12 sided die)
>A d20 (a 20 sided die)
>These have all regular shapes (latin names tertaaeder, octaeader, etc.)

>But we also have
>D10 (a ten sided die) and a D30 (a thirty sided die).
>These have a irregular shape (D10 looks like a D8 but has 10 sides(5 
>up and 5 down) instead of 8 (4 up and 4 down)
>
>Is it true that the regular shaped dice are more random than the 
>irregular shaped dice. And why is that so?

You may notice that I corrected your words that refer to dice. One die plus one 
die equals two dice.
As a starting hypothesis, I would guess that the probability of a die landing 
with a particular side up would depend on the surface area of the side that is 
opposite it (the down side). It could conceivably also depend to some extent on 
angles between the sides, but I would not be able to predict or explain those 
effects. You would need to do a series of throws and see what fraction of the 
time each side came up. The process is certainly random but you are really 
asking whether the odds of a particular value coming up is uniform across all 
possible results. It would take a substantial number of throws to develop a 
statistically valid sample to test the hypothesis that the odds are not equal. I 
would guess that you would need 300-400 throws for a ten sided die and maybe ten 
times that number for a 30 sided die. Do you have a lot of time? If so send me 
the results and I'll see what I can cook up. The other place to send the 
question would be the newsgroup sci.stat.consult.

David Winsemius, MD, MPH