[pct-l] Probability of Disaster

[Yoshihiro Murakami]

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.











>
> Probability of success:
> How many PCTers have reached Canada with a pack in the neighborhood
> of (I'll be generous) 45 or more lbs?
>
> Just browsing google image search, most people look to be carrying
> typical thru-hiker gear of sub 20lbs. Little packs go far.
> Traditional heavy-weight packs do not.
>
> Ultralight isn't just a fashion. It was born out of the necessity of
> thru-hikers who want to get to Canada before the snow flies. I would
> say the typical ultralight hiker standing on the Canadian border has
> better equipment than the typical, over-loaded, what-iffed to
> insanity traditional backpacker.
>
> Ned just wants to scare people into taking his class. He need not do
> that. He need not gloat every time snow falls somewhere on the trail
> and start preaching about the need for ice axes in July and -15
> degree bags in August (Holy cow! How many people can actually sleep
> with a bag 45 degrees too hot?). Plenty of people would like to learn
> how to self-arrest and walk on snow safely. They are not interested
> in how to backpack like the days of yore before silnylon and titanium
> and they're turned off by someone purposefully confusing a light
> dusting of snow on the trail for a life-threatening storm requiring
> Everest expedition equipment.
>
> Sorry to be so blunt.
>
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-- 
Sincerely
--------------- --------------------------------------
Hiro    ( Yoshihiro Murakami )
HP    http://psycho01.edu.u-toyama.ac.jp
Blogs http://completewalker.blogspot.com/
Photo http://picasaweb.google.co.jp/CompleteWalker/
Backpacking for 30 years in Japan
2009 JMT, the first America.
------------------------------------------------------