There is a min but no max.  You can calculate a 95% or 99% confidence interval 
but there are possibilities where the one prisoner that turns off the light 
never is chosen enough to switch it off 99 times. A Long Tail.

Donna
[email protected]


On 2012-09-11, at 12:38 PM, Pierpaolo Bernardi <[email protected]> wrote:

> On Tue, Sep 11, 2012 at 6:31 PM, Jordan Tirrell <[email protected]> 
> wrote:
>> So after looking back at my computation, I noticed that I had forgotten a
>> final step: dividing by 100. Now it looks like we're all in the 1e4
>> ballpark.
>> 
>> My computation is pretty short to write, but it will be hard to understand
>> if you aren't familiar with generating functions.
>> 
>>   G=: (1+i.99)&(*/@:((**:)%(1-99*])*1-*))
>>   (*(G D. 1)) %100
>> 10423.2
>> 
>> Pierpaolo's estimate is incredibly close to my computation.
> 
> 8^)
> 
> Here's what I get with my simulation (alas, not written in J):
> 
>> (test 100 ; number of prisoners
>            10000  ; number of experiments
>    )
> 
> 10418.0462   ; average number of days
> 7222.0          ; minimum number of days occurred
> 14522.0        ; maximum =    =    =    =
> 
> 
> Cheers
> P.
> 
>> 
>> 
>> 
>> 
>> 
>> On Tue, Sep 11, 2012 at 12:09 PM, Roger Hui <[email protected]>wrote:
>> 
>>> 100 Prisoners Simulation:  Assume without loss of generality that prisoner
>>> 0 is the designated "counter".  A "round" is a group of selections (one per
>>> day) with prisoner 0 as the fret.  Thus:
> 
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