Re: Random or pseudorandom? ...

Ertugrul Söylemez <es@xxxxxxxx> writes:
Unruh <unruh-spam@xxxxxxxxxxxxxx> wrote:
Ertugrul =?UTF-8?B?U8O2eWxlbWV6?= <es@xxxxxxxx> writes:

If I take somebody off the street and ask them to "tell me 10
random numbers", are their numbers random or pseudorandom ?

Random. This is clear if you first define random and
pseudorandom.

How can you know whether or not they have been randomly generated?

They are not. Try it and look at the distribution of the numbers
you get. For example, 7 will occur far more frequently than 1/10
because people will say "1 2 or 3 clearly are not random, nor is
9. 4 and 8 are multiples of 2 so are clearly not random, and 5
being 1/2 of 10 is not random." Ie, the numbers someone off the
street will give you will NOT be "unpredictable" which is one of
the definitions of random.

This is bias, not predictability. The numbers are still random. If
you ask someone on the street, you (generally) can't predict the
outcome. If you, on the other hand, ask a thousand people, you can
predict, which numbers appear more often than others.

Ah, so if everyone picks 7 that is not non-random, it is simply
biased. A biased distribution IS a non-random distribution.

Humans are more random than that. If you pick only two candidates,
getting two sevens is quite likely, but this is just likely, not
guaranteed.

It is generally assumed that if the word 'random' is used in
a context where no distribution is mentioned, then a uniform
distribution is to be assumed.

You may not like that assumtion, but if you don't make it,
you certainly can't make any alternative assumption, and
therefore the word 'random' becomes entirely useless, as it
means nothing.

Phil
--
The fact that a believer is happier than a sceptic is no more to the
point than the fact that a drunken man is happier than a sober one.
The happiness of credulity is a cheap and dangerous quality.
-- George Bernard Shaw (1856-1950), Preface to Androcles and the Lion
.

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