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Path: utzoo!linus!genrad!decvax!cca!ima!johnl
From: johnl@ima.UUCP
Newsgroups: net.math
Subject: Re: Speaking of random numbers.... - (nf)
Message-ID: <346@ima.UUCP>
Date: Fri, 17-Jun-83 18:40:01 EDT
Article-I.D.: ima.346
Posted: Fri Jun 17 18:40:01 1983
Date-Received: Sat, 18-Jun-83 16:38:51 EDT
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#R:ihuxi:-44100:ima:16700001:000:827
ima!johnl    Jun 17 11:57:00 1983

WRT the Illinois lottery:

    Unfortunately, it is also easy to show that if the probability of
    winning the grand prize is p, if you play the game 1/p times, you
    have a 50% chance of not having won the prize yet!

Not quite.  That formula assumes that the chances of winning on each play
are independent.  In lotto games you get to pick your own numbers, so
they are not.  You could (assuming your grocery store had 1.9 million
entry forms) bet on all possible combinations and win the grand prize, as
well as all of the subsidiary prizes, too.

I suspect that this doesn't happen because people with $2 million to
invest and a phenomenally large pencil (to fill out all of those lotto
forms) are few and far between.

John Levine, decvax!yale-co!jrl, ucbvax!cbosgd!ima!johnl,
{research|allegra|floyd|amd70}!ima!johnl