Article View: alt.folklore.science
Article #963Re: Shell Game (Dixie cups work too)
From: Henry Melton
Date: Mon, 14 Dec 1992 22:50
Date: Mon, 14 Dec 1992 22:50
155 lines
6648 bytes
6648 bytes
In article <Mf_daCm00WBN43v2El@andrew.cmu.edu> "Stephen M. Lacy" <sl31+@andrew.cmu.edu> writes:
>Excerpts from netnews.alt.folklore.science: 11-Dec-92 Shell Game (Dixie
>cups work.. by checkett@dbsun.uucp
>> Here's the questions:
>> Should the player switch to the other cup or stay pat?
>> What are the odds?
>
>HAVE YOU NOT HEARD OF THIS PROBLEM BEFORE! Gawd, there was an entire
>multi-million television game show based exactly on this proposiiton!
>(The Monty Hall show, if you couldn't remember) The correct answer (I
>believe) is that you definately want to switch no matter what. The odds
>are in your favor to some non-significant amount. I think its something
>like 66% win if you switch, but I forget the numbers.
>
>Steve
main()
{
int winning_door;
int first_guess;
int swap_win = 0;
int stay_win = 0;
float swap;
float stay;
while(1)
{
/* Monty Hall shows 3 doors, one of which is the winner */
winning_door = (rand() % 3 ) + 1;
/* The contestant guesses a door */
first_guess = (rand() % 3 ) + 1;
/* Monty Hall shows one of the bad doors and allows
offers the chance to swap */
if (winning_door == first_guess)
stay_win++;
else
swap_win++;
stay = (100.0 * stay_win) / ( stay_win + swap_win);
swap = (100.0 * swap_win) / ( stay_win + swap_win);
printf ("%d %d -- Swap wins %7.4f Stay wins %7.4f\n",
winning_door,
first_guess,
swap,
stay);
}
}
3 2 -- Swap wins 100.0000 Stay wins 0.0000
1 2 -- Swap wins 100.0000 Stay wins 0.0000
2 3 -- Swap wins 100.0000 Stay wins 0.0000
1 1 -- Swap wins 75.0000 Stay wins 25.0000
1 1 -- Swap wins 60.0000 Stay wins 40.0000
2 3 -- Swap wins 66.6667 Stay wins 33.3333
1 1 -- Swap wins 57.1429 Stay wins 42.8571
3 3 -- Swap wins 50.0000 Stay wins 50.0000
1 1 -- Swap wins 44.4444 Stay wins 55.5556
1 1 -- Swap wins 40.0000 Stay wins 60.0000
3 2 -- Swap wins 45.4545 Stay wins 54.5455
3 1 -- Swap wins 50.0000 Stay wins 50.0000
1 1 -- Swap wins 46.1538 Stay wins 53.8462
1 3 -- Swap wins 50.0000 Stay wins 50.0000
2 3 -- Swap wins 53.3333 Stay wins 46.6667
3 3 -- Swap wins 50.0000 Stay wins 50.0000
3 2 -- Swap wins 52.9412 Stay wins 47.0588
3 3 -- Swap wins 50.0000 Stay wins 50.0000
2 2 -- Swap wins 47.3684 Stay wins 52.6316
1 1 -- Swap wins 45.0000 Stay wins 55.0000
3 3 -- Swap wins 42.8571 Stay wins 57.1429
1 1 -- Swap wins 40.9091 Stay wins 59.0909
2 3 -- Swap wins 43.4783 Stay wins 56.5217
1 3 -- Swap wins 45.8333 Stay wins 54.1667
3 1 -- Swap wins 48.0000 Stay wins 52.0000
1 3 -- Swap wins 50.0000 Stay wins 50.0000
2 3 -- Swap wins 51.8519 Stay wins 48.1481
1 2 -- Swap wins 53.5714 Stay wins 46.4286
1 2 -- Swap wins 55.1724 Stay wins 44.8276
3 2 -- Swap wins 56.6667 Stay wins 43.3333
2 2 -- Swap wins 54.8387 Stay wins 45.1613
2 1 -- Swap wins 56.2500 Stay wins 43.7500
2 1 -- Swap wins 57.5758 Stay wins 42.4242
1 3 -- Swap wins 58.8235 Stay wins 41.1765
3 2 -- Swap wins 60.0000 Stay wins 40.0000
2 2 -- Swap wins 58.3333 Stay wins 41.6667
3 1 -- Swap wins 59.4595 Stay wins 40.5405
2 1 -- Swap wins 60.5263 Stay wins 39.4737
2 2 -- Swap wins 58.9744 Stay wins 41.0256
2 1 -- Swap wins 60.0000 Stay wins 40.0000
3 1 -- Swap wins 60.9756 Stay wins 39.0244
2 1 -- Swap wins 61.9048 Stay wins 38.0952
2 2 -- Swap wins 60.4651 Stay wins 39.5349
2 2 -- Swap wins 59.0909 Stay wins 40.9091
1 3 -- Swap wins 60.0000 Stay wins 40.0000
3 3 -- Swap wins 58.6957 Stay wins 41.3043
1 1 -- Swap wins 57.4468 Stay wins 42.5532
2 2 -- Swap wins 56.2500 Stay wins 43.7500
3 1 -- Swap wins 57.1429 Stay wins 42.8571
3 2 -- Swap wins 58.0000 Stay wins 42.0000
1 1 -- Swap wins 56.8627 Stay wins 43.1373
1 1 -- Swap wins 55.7692 Stay wins 44.2308
1 3 -- Swap wins 56.6038 Stay wins 43.3962
3 3 -- Swap wins 55.5556 Stay wins 44.4444
3 2 -- Swap wins 56.3636 Stay wins 43.6364
2 1 -- Swap wins 57.1429 Stay wins 42.8571
3 2 -- Swap wins 57.8947 Stay wins 42.1053
1 2 -- Swap wins 58.6207 Stay wins 41.3793
2 2 -- Swap wins 57.6271 Stay wins 42.3729
2 1 -- Swap wins 58.3333 Stay wins 41.6667
3 3 -- Swap wins 57.3770 Stay wins 42.6230
3 1 -- Swap wins 58.0645 Stay wins 41.9355
3 1 -- Swap wins 58.7302 Stay wins 41.2698
2 3 -- Swap wins 59.3750 Stay wins 40.6250
1 2 -- Swap wins 60.0000 Stay wins 40.0000
2 3 -- Swap wins 60.6061 Stay wins 39.3939
2 3 -- Swap wins 61.1940 Stay wins 38.8060
1 3 -- Swap wins 61.7647 Stay wins 38.2353
3 2 -- Swap wins 62.3188 Stay wins 37.6812
1 3 -- Swap wins 62.8571 Stay wins 37.1429
2 2 -- Swap wins 61.9718 Stay wins 38.0282
3 1 -- Swap wins 62.5000 Stay wins 37.5000
2 2 -- Swap wins 61.6438 Stay wins 38.3562
1 3 -- Swap wins 62.1622 Stay wins 37.8378
2 3 -- Swap wins 62.6667 Stay wins 37.3333
1 3 -- Swap wins 63.1579 Stay wins 36.8421
1 2 -- Swap wins 63.6364 Stay wins 36.3636
3 2 -- Swap wins 64.1026 Stay wins 35.8974
2 1 -- Swap wins 64.5570 Stay wins 35.4430
3 2 -- Swap wins 65.0000 Stay wins 35.0000
3 1 -- Swap wins 65.4321 Stay wins 34.5679
1 2 -- Swap wins 65.8537 Stay wins 34.1463
2 2 -- Swap wins 65.0602 Stay wins 34.9398
3 2 -- Swap wins 65.4762 Stay wins 34.5238
3 2 -- Swap wins 65.8824 Stay wins 34.1176
1 1 -- Swap wins 65.1163 Stay wins 34.8837
2 3 -- Swap wins 65.5172 Stay wins 34.4828
2 2 -- Swap wins 64.7727 Stay wins 35.2273
3 2 -- Swap wins 65.1685 Stay wins 34.8315
3 3 -- Swap wins 64.4444 Stay wins 35.5556
3 3 -- Swap wins 63.7363 Stay wins 36.2637
1 1 -- Swap wins 63.0435 Stay wins 36.9565
3 3 -- Swap wins 62.3656 Stay wins 37.6344
2 3 -- Swap wins 62.7660 Stay wins 37.2340
3 1 -- Swap wins 63.1579 Stay wins 36.8421
1 2 -- Swap wins 63.5417 Stay wins 36.4583
2 2 -- Swap wins 62.8866 Stay wins 37.1134
2 1 -- Swap wins 63.2653 Stay wins 36.7347
3 1 -- Swap wins 63.6364 Stay wins 36.3636
3 2 -- Swap wins 64.0000 Stay wins 36.0000
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Newsgroups: alt.folklore.science Path: arc1-ca.pugleaf.net!sparky!uunet!spsgate!mogate!newsgate!melton.sps.mot.com!rhca80 From: rhca80@melton.sps.mot.com (Henry Melton) Subject: Re: Shell Game (Dixie cups work too) Message-ID: <1992Dec14.225009.27216@newsgate.sps.mot.com> Sender: usenet@newsgate.sps.mot.com Nntp-Posting-Host: 222.1.248.94 Organization: /etc/organization References: <Mf_daCm00WBN43v2El@andrew.cmu.edu> Date: Mon, 14 Dec 1992 22:50:09 GMT Lines: 155