[pct-l] Probability of Disaster

[greg mushial]

>
> Message: 1
> Date: Thu, 2 Sep 2010 12:19:47 +0900
> From: Yoshihiro Murakami <completewalker at gmail.com>
> Subject: Re: [pct-l] Probability of Disaster
> To: Diane Soini of Santa Barbara Hikes <diane at santabarbarahikes.com>
> Cc: pct-l at backcountry.net
> Message-ID:
> <AANLkTiktF8q0vs3_+t3p5583w8pnMJuvwXSeT4ioJXRK at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> A few study was done.  Anderson et al.(2009, Wilderness and
> Environmental Medicine, 20, 250-256), studied the 128 long distance
> hikers who walked AT or PCT.
>
> Their basic pack weight were
> 10-20   52 ( 34.9%)
> 21-30   37( 30.1%)
> >=31    34(27.6%)
>
> Footwear
> Hiking boots   44( 34.9%)
> Low-top hiking boots 27(21.4%)
> Running shoes       48(38.1%)
> Sandals                    7(5.6%)
>
> Increasing pack weight was associated with increasing the
> paresthesias, but not with the musculoskeletal injuries.
>
> Footwear type was not associated with the injuries, simply because
> heavy packs user wears heavy boots. So, when the heavy pack user wears
> shoes, the danger of injury will appear.
>
> So, based of this article, the light weight backpacking  has a effect
> of reducing the paresthesias, but no effect of reducing the injuries.
>
>
> ---------------------
>
> Concerning the probability,
>
> 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.

Besides, a learned understanding of probability is a whole lot more useful 
in dealing with real life...  welcome back Yoshihiro - hope the trip was a 
good one [will you be posting pictures?? please ;-)   ]