[dba-Tech] The Three Doors Problem

Ok found it.
Its called the Monty Hall rule.
I programmed it in the boxes version (there are many version of this
rule).
My code was programmed in VB6 but its pretty simple and will probably
work straigt away in VBA to.

Run the MontyHall sub adding the number of iterations.
As usual statistics are more accurate with larger numbers.
But you alreay see it with 10 iterations.


Here's the code. 
###BEGIN OF CODE###
Sub MontyHall(Iterations As Long)
Dim Success As Integer
Dim Boxes(3) As Boolean
Dim Choosen As Integer
Dim Unvealed As Integer
Dim NoChangeSuccess As Long
Dim ChangeSuccess As Long
Dim NoChangeTotal As Long
Dim ChangeTotal As Long
Dim NotChoosen As Integer

Dim I As Integer, Iteration As Long

For Iteration = 1 To Iterations
NoChangeSuccess = 0
ChangeSuccess = 0

    For I = 1 To 100
        Erase Boxes
        
        'Set money in box
        Randomize
        Boxes(Int((3 * Rnd) + 1)) = True
    
        'I'm Choosing a box
        Randomize
        Choosen = Int((3 * Rnd) + 1)
        
        
        'Unveale 1 empty box
        Unvealed = Int((3 * Rnd) + 1)
        Do Until Unvealed <> Choosen
            Randomize
            Unvealed = Int((3 * Rnd) + 1)
        Loop
        If Boxes(Unvealed) = True Then Unvealed = 6 - Choosen - Unvealed
        
        
        'Check for values
        NotChoosen = 6 - Choosen - Unvealed
        If Boxes(Choosen) = True Then NoChangeSuccess = NoChangeSuccess
+ 1
        If Boxes(NotChoosen) = True Then ChangeSuccess = ChangeSuccess +
1
    
    Next I
    
    'Remove Remark on folowing line for detailed results
    'Debug.Print "Iteration:" & Format(Iteration, "00#") & " Result
Choosen Box:" & NoChangeSuccess & " Other box:" & ChangeSuccess
    
    'Set totals
    NoChangeTotal = NoChangeTotal + NoChangeSuccess
    ChangeTotal = ChangeTotal + ChangeSuccess
    
    
Next Iteration

Debug.Print "Iterationtotals:" & " Result Choosen Box:" & NoChangeTotal
/ Iterations & "% Other box:" & ChangeTotal / Iterations & "%"

End Sub
###END OF CODE###





 

-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of Erwin Craps
- IT Helps
Sent: Friday, August 26, 2005 7:54 AM
To: Discussion of Hardware and Software issues
Subject: RE: [dba-Tech] The Three Doors Problem

Ha, seen this a couple of years ago but with dead row prisoners...
I written an VBA program to take this statistical weirdness to the test
AND IT IS TRUE

I try if I can find the program...


-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of Josh
McFarlane
Sent: Friday, August 26, 2005 7:22 AM
To: Discussion of Hardware and Software issues
Subject: Re: [dba-Tech] The Three Doors Problem

Well, that one is a little bit more simple.

Barrel A, Barrel B, and Barrel C
Fruit - Apples -- Oranges

If he pulls Apples out of Barrel A, you apply Apples to Barrel A,
Oranges to Barrel B and Fruit to Barrel C, just a matter of making sure
the same label doesn't end up on the same spot.

In the case of the game show problem however, you start out with 3
choices to resolve the situation:

2 Losses
1 Win

No matter what you choose, the situation is simplified to two choices:

1 Loss
1 Win

The other properties of the choice don't change, as there will always be
1 win and 1 loss. Nothing says either or will be more probable than the
other, so you should end up with a 50/50 chance.

On 8/25/05, MartyConnelly <martyconnelly at shaw.ca> wrote:
> Well this is a microsoft interview question You have three barrels 
> labelled oranges, apples and mixed fruit The barrels have all  been 
> mislabelled, Someone pulls out a fruit from a barrel and tells you it 
> is an apple your job is to relabel the barrels correctly.
> 
> Stuart McLachlan wrote:
> 
> >On 25 Aug 2005 at 19:52, Kathryn Bassett wrote:
> >
> >
> >
> >>I know the answer is to stick with original choice, but I can't
remember the logistics of why.
> >>
> >>--
> >>
> >>
> >Bzzzt!
> >
> >Next?
> >
> ><g>
> >
> >
> >
> 
> --
> Marty Connelly
> Victoria, B.C.
> Canada
> 
> 
> _______________________________________________
> dba-Tech mailing list
> dba-Tech at databaseadvisors.com
> http://databaseadvisors.com/mailman/listinfo/dba-tech
> Website: http://www.databaseadvisors.com
> 


--
Darsant Silverstring 

"Peace cannot be kept by force. It can only be achieved by
understanding."
-Albert Einstein
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