
From:  tchow 
Subject:  Re: [Buggnubg] random dice generator? hahahaaa 
Date:  Sat, 26 Aug 2017 17:21:21 0400 
Useragent:  Roundcube Webmail/0.9.5 
Oystein SchonningJohansen wrote:
Now the interesting part: How can you construct a scientific test to prove(or falsify) the postulate that a software uses such scheme?
Assuming that you mean statistical proof, it depends on what you're trying to establish. If you're just trying to establish nonrandomness then simply counting how often a roll appears twice in a row should be a pretty strong test. In a random sequence, the probability that the next roll will be the same as the current roll is 1/36 if it's a doublet and 1/18 if it's a nondoublet. In the system I described, I think the probability is (1/18)*(1/36) for a doublet and (17/18)*(1/36) + (1/18)*(1/18) for a nondoublet. I'm too lazy to work out how many rolls it would take to reach 95% confidence but I'd guess that a few dozen rolls would suffice.
If you're trying to establish in detail what the algorithm is doing then it's obviously going to require more data. How much data exactly depends on what alternative hypotheses you're willing to entertain.
Tim
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