Ummmm...What's the Probability that this thread will die within the next 24 hours??? ??????     :)

James

-----Original Message-----
From: Gavin Scott
Sent: Wednesday, March 01, 2000 12:10 PM
To: [log in to unmask]
Subject: Re: OT: Probability question


Gary puzzles along with the rest of us:
> Every time I hear this one I scratch my head in confusion.

The virtual coins don't lie:

   10 REM contestant's Choice, prize Door, door Exposed by monty
   20 INTEGER C,D,E
   30 REM Total games, wins if the user Holds, winds if he Switches
   40 LONG T,H,S
   50 T=H=S=0
   60 FOR I=1 TO 1000
   70   REM Prize is behind...
   80   D=INT(RND(0)*3+1)
   90   REM Contestant Chooses...
  100   C=INT(RND(0)*3+1)
  110   REM Monty Exposes...
  120   E=INT(RND(0)*3+1)
  130   IF E=C OR E=D THEN 120
  140   REM If user holds on...
  150   IF C=D THEN H=H+1
  160   REM If user switches...
  170   IF C=1 THEN DO
  180     IF E=2 THEN C=3
  190     IF E=3 THEN C=2
  200     GOTO 320
  210   DOEND
  220   IF C=2 THEN DO
  230     IF E=1 THEN C=3
  240     IF E=3 THEN C=1
  250     GOTO 320
  260   DOEND
  280   IF E=2 THEN C=1
  290   IF E=1 THEN C=2
  320   IF C=D THEN S=S+1
  330   T=T+1
  340 NEXT I
  350 PRINT USING 360;T,H,S
  360 IMAGE 8D,2X,8D,2X,8D
>run
    1000       363       637

So for 1000 trips to the Big Deal of the Day, keeping the original choice
resulted in 363 wins, but switching resulted in 637 wins!

G.