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Re: Dice

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Re: Dice

Subject: Re: Dice
From: email@hidden
Date: Fri, 29 Oct 2004 11:18:12 -0400

At 7:48 PM +0200 10/26/04, Emmanuel wrote:

At 12:46 PM -0400 10/26/04, Graff wrote:
I just ran it 1000 times and got the following distribution:
1    161
2    167
3    173
4    170
5    169
6    160
std deviation = 5.16
So no, it doesn't seem to be perfect but it's probably good enough for most applications.
Out of curiosity, what would the std deviation be if the random was perfect?

There isn't such a number. If the sequence is actually random it will vary depending on the trial. Certain ranges indicate a high likelihood of non-randomness. Distributions with SD very close to zero, or very high relative to the total trials would be good evidence of a non-randomness (this is what the chi-square test does). There's a standard (fairly hard) formula for determining the chance that a random generator would produce a distribution that is over/under some given standard deviation.

There isn't going to be any SD that's proof of randomness. Even (but not *too* even) distribution is just one of many things that should be true of a random sequence. But there a millions of ways for a sequence to ahve a distribution consistent with randomness without remotely useful as a general purpose random number generator.

For everything you ever wanted to know about random numbers and more, start surfing around from www.random.org until you get bored or your brain explodes.


Michael

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References:  
  >Re:Dice (From: Kevin <email@hidden>)
  >Re: Dice (From: Adrian Milliner <email@hidden>)
  >Re: Dice (From: Robert Poland <email@hidden>)
  >Re: Dice (From: Graff <email@hidden>)
  >Re: Dice (From: Emmanuel <email@hidden>)




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