[gurps] declining probability

[Captain Joy]

On Monday, June 18, 2007, at 11:57  PM, Captain Joy wrote:

> On Monday, June 18, 2007, at 10:48  PM, Max, Dunedin, NZ wrote:
>> Captain Joy wrote:
>>> Here is what I came up with:
>>>     Avg # or rolls to till you hit 0 given a starting no. to beat
>>> 3    3.0046511628
>>> 4    4.0235190873
>>> 5    5.0720627766
>>> 6    6.174103593
>>> 7    7.3674737587
>>> 8    8.7174737587
>>> 9    10.317473759
>>> 10    12.317473759
>>> 11    14.984140425
>>> 12    18.841283283
>>> 13    25.012711854
>>> 14    35.812711854
>>> 15    57.412711854
>>> 16    111.41271185
>>> 17    327.41271185
>>> 18    infinite
>>
>> Just one note, it won't make to much difference to the results, but 
>> as this is GURPS, the statistics are slightly different, ie a 17 & a 
>> 18 are always a failure, which means 18 won't be infinite.
>
> Oh, you're right about that.  Well, given that 17 and 18 are always 
> failures, then the results for 17 and 18 will be exactly the same as 
> for 16.

Nope, it's not that simple.  As average number of rolls until a failure 
to roll a 16 is 54, I think the rest of the chart should look like:

16	111.4
17  265.4
18  319.4
--
captainjoy at mac.com
"In these days of cold affections.  You sit by me - and everything's 
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