Monday, September 27, 2010

Review: Gamescience Dice Part 2

Continued from Part 1:

Now, are they actually balanced?  I did a completely non-scientific study of my dice.  I made 1,000 rolls each on both my old Chessex dice and the new Gamescience dice.  I'm loath to publish my results because they are pretty non-scientific but here they are.  The rolls were made on a hard surface.  I picked 5 dice at random out of my pool for each roll.

Chessex Results:

1:  15.8%
2:  17.4%
3:  18.2%
4:  15.2%
5:  16.5%
6:  16.9%

Average roll:  3.499

1:  15.5%
2:  18.1%
3:  13%
4:  16.3%
5:  19.2%
6:  17.9%

Average roll:  3.594

So it would appear that the Gamescience dice roll higher and the Chessex roll lower but closer to average.  This is where I think my results are flawed.  I don't know enough about probability to say if 1k rolls are enough to really determine an average.  And if the Gamescience dice do indeed roll higher, am I an unethical gamer if I use them and I know they roll higher?  Am I a total nerd if I made 2k rolls to see if my dice really are biased?

In the end most gaming rolls are made on a felt surface.  I probably need to redo the test on a felt gaming board but I really don't feel like doing it again.  Furthermore, when I roll my dice I try and bounce them for best results.  I also own a dice tower and I wonder how the results would be there.  So I don't think I can count these results.  Further tests are needed.

Final Verdict, the Bad:  The sharp corners of Gamescience dice kind of hurt my hands and they're a bit bigger than the usual dice so it's hard to pick up a big handful of them.  The clear non-inked ones are hard to read (if you buy the clear get inked) sometimes.  They're more expensive than Chessex dice and are not sold in bricks.

Final Verdict, the Good:  They don't go bouncing every which way when you roll them or when they fall on the floor.  Also, this will sound really stupid but I feel more confident rolling them, that I know if I get bad dice rolls it's because of probability not because of flaws in my dice.  The greatest plus of all is that if they are truly statistically even, that should outweigh all other considerations.

So for anyone who knows more about probability and statistics than I (which isn't much), I'd appreciate you weighing in.

2 comments:

  1. I don't know a whole lot more about probability, other than to say this:

    1000 is a good sample size. (Consider how many rolls you'd make a game - this means the sample is probably an average games worth)

    As for using felt, there's lots of different kinds of felt and felt-like materials that could be rolled on. An even flat surface is a really good test case and the important thing is both sets of dice were rolled on the same surface.

    I think you've done a great test here and determined that both types of dice are pretty much the same.
    I'd also like to point out that if they have mold lines you have to clean off - they don't sound professional. Especially since the very act of cleaning off the lines will actually affect the balance of your dice.

    "More random" is really just a selling point.

    I'm pretty sure this is the same guy, but basically he had an online random number generator and people complained to him that his rolls "weren't random enough". He finally snapped and built a giant industrial machine that can now roll 1.3 million dice a day and photograph the results of each roll, uploading the results to his website.
    http://gamesbyemail.com/News/DiceOMatic

    If you feel like turning this into a project, I'd recommend this:
    - Determine the average number of rolls, both sides, per game. (This should be in same number of points games)
    - Multiply that by how many games would be played in a tournament of equal points values. (A tournament seems like a good sample size) Even better would be to count the total number of dice rolls in a tournament, to factor in different types of armies. (Marines are going to roll less than nids for example)
    - Roll that many times.

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  2. Thanks for the comment. The mold line isn't really a mold line, it's more like a mold mark. I wasn't too clear on that. Its position on the dice wouldn't affect any rolls if you left it, I simply removed it for aesthetics. Chessex and all other types of non-machined dice have that same mold line, but they tumble the dice to get rid of it hence the unevenness because the process is inaccurate. Casino dice aren't cast, they're machined so they have no mold line. They are also heavy and expensive. I'd be afraid of someone rolling them on a table and chipping my paint.

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