[pct-l] Probability of Disaster

[Tortoise]

In accidents there are usually a chain of errors/mistakes which lead to the 
fatality.

for instance -- hiker dies in a blizzard on JMT in summer.

chain of mistakes / errors may be:
1.  ignoring weather forecast of incoming storm,
2.  ignoring or not knowing weather indications while on the trail,
3. lack of experience and/or knowledge of survival in snow storms.
4.  leading to not taking proper shelter in the storm, and
5. other gear inadequate or not used so as to survive storm.
6. maybe inadequate conditioning / stamina to reach safer location such as 
bailing down a side trail.
7. good or bad luck (bad luck: feet too sore to travel and caught. / good 
luck: sore feet causing one to leave trail or not even getting to the 
danger zone.

So estimating the probability of a bad occurrence is, as you said, very 
difficult and also very imprecise.


Tortoise

<> Because truth matters! <>

On 09/01/10 20:19, Yoshihiro Murakami wrote:

>
> if bad things happen at probability 0.1 ( assuming events are
> independent as Jim and Jane said, when events are dependent, difficult
> to analyze)
>
> Assuming
> bad event1... 0.1
> bad event2 ... 0.1
> bad event3 ...0.1
>
> The probability of no occurrence of bad events is
>
> (1 -0.1 ) X (1 - 0.1 ) X ( 1 - 0.1 ) ..... -->  0.9 X 0.9 X 0.9 = 0.729
>
> Then the probability of bad events is
>
> 1 - 0.729 = 0.271
>
> The intuitive thinking of probability often misleading.
>