On Mon, 20 Dec 1999, Eduardo Chappa L. wrote (privately):
> Thanks for your message. I learned all this stuff about combinations a
> long time ago and I think about these problems in the same way as you do,
> except, maybe, at the end.
Thanks for being so gentle. It would have been just as easy to
say "You talked about combinations, but used the formula for
permutations." A fairly big goof, which changes the interpretation of
the results. The 20! makes the chance of being a unique combination
much higher, and the chance of duplication vanishingly small. I guess
it has been too many years since I worked with probability regularly.
The error would have been obvious to me a few years ago, without
anyone having to point it out.
Correct formula for chance of duplicate values (20 from pool of 10000)
1 - ( 9999! / (9980! * 10E76 * 20!))
It certainly is humbling to be so wrong in public. Thanks for not
letting the misinformation stand.
Doug
__
Doug Kaufman
Internet: [EMAIL PROTECTED]
