RE: random integer weirdness
- To: mathgroup at smc.vnet.net
- Subject: [mg35787] RE: [mg35772] random integer weirdness
- From: "DrBob" <majort at cox-internet.com>
- Date: Wed, 31 Jul 2002 01:33:24 -0400 (EDT)
- Reply-to: <drbob at bigfoot.com>
- Sender: owner-wri-mathgroup at wolfram.com
That IS bizarre. The following works much better, though it may have
other statistical problems:
sim = Table[{j, Mean[Table[Ceiling[Random[]2^j], {n}]]
2^(1 - j)}, {j, 45, 65, 1/8}];
ListPlot[sim];
Bobby Treat
-----Original Message-----
From: Mark Fisher [mailto:mark at markfisher.net]
To: mathgroup at smc.vnet.net
Subject: [mg35787] [mg35772] random integer weirdness
There is some real weirdness with Random[Integer, j] for some large
values of j but not others (for both 4.1 and 4.2 versions).
<<Statistics`
n = 1000;
sim = Table[{j, (2/2^j) * Mean[Table[Random[Integer, 2^j], {n}]]},
{j, 45, 65, 1/8}];
ListPlot[sim];
All the points should be near one if the random number generator were
working properly. What gives? Is this just a (very stark) symptom of
what Daniel Lichtblau mentioned in his May 2000 post?
>> The other failure only is apparent in very large big
>> integers, and I do not know exactly how to categorize it.
I just find this very troubling.
--Mark.