Hugo Mills said the following on 14/05/08 23:46:
> On Wed, May 14, 2008 at 11:37:33PM +0100, Chris Oattes wrote:
>> Nick Chalk said the following on 14/05/08 22:56:
>>> Peter Alefounder <p_alefounder@???> wrote:
>>>> Why are pseudo-random numbers used anyway? Is it
>>>> beyond the wit of man to devise a bit of
>>>> hardware that would produce genuine random
>>>> numbers?
>>> What is a "genuine" random number?
>>>
>> As I understand it, a "genuine" random number is as follows:
>>
>> Assume you have a stream of numbers in base 10 (i.e. made up of a series
>> of digits from 0-9).
>>
>> This stream of numbers would be considered random if, given the first x
>> digits, it is impossible to determine the x+1 th digit with probability
>>> 1/10. That is to say, each digit is equally likely to be any one of
>> the possible values.
>>
>> I'm sure I will be corrected if I am wrong.
>
> Not wrong, possibly, but not helpful in practice. If I gave you a
> list of 100,000 numbers, could you use that definition to show that it
> was a stream of random numbers?
>
> Hugo.
>
>
I was simply trying to define what a "genuine" random number is, not how
to test for one. I suspect that it would be possible to use this
definition by stating that, after performing some analysis on the number
you were able to predict the next number with probability > 1/10 a
statistically significant number of times, the stream is probably not
random.
To declare a stream of numbers genuinely random, you would probably need
to know more about how it was generated.
Disclamer: I am only a Computer Science student, not a Mathematician
Chris.
