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Monty Hall problem solved (this is stupid)
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monty = function() | |
{ | |
/* | |
Assumptions: | |
1. The host will always give you a second choice. | |
2. The host will never open the door with the prize | |
because that would end the mystery. | |
Hypothesis: | |
Most people are right and this is math foolishness. This is not | |
the prisoner's dilemma. This is liar's paradox which is solved | |
by asking the liar what the truth-teller would say and doing | |
the opposite. | |
Parameters: | |
The monty function takes a number, either 2 or 3 and | |
returns [ 0,1,2 ] or [ 0,1 ]. You | |
always choose door 2 and the host always opens door 0 | |
or 1. Randomly chosing a different door doesn't change | |
the outcome over time. | |
*/ | |
monty_ = function(x) { return Math.floor(Math.random(1) * x); } | |
win = 0; | |
lie = 0; | |
for( x = 0; x < 1000000; x++) { | |
door = monty_(3); | |
lie = monty_(2); | |
if(door == 2) { | |
if(lie)win++; } | |
else | |
if(door == 1) | |
if(lie)win++; | |
} | |
console.log( win / 10000 ); | |
/* By running monty_ repeatedly with "3", we obviously get | |
a 33% success rate across the million executions. We | |
would get the same with a trillion or a zillion | |
zillion. Making the number larger is pointless. Running | |
monty_ with "2" a million, billion, or trillion times would also | |
give us a 50% success rate. No need to do this. So the | |
only thing we can do is run monty(2) against the | |
results of monty(3) and see if the win rate changes. With | |
this version, we still get the same odds. */ | |
} |
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