Re: certainty versus uncertainty

[Bob Sciamanda <Sciamanda@worldnet.att.net>]

LUDWIK KOWALSKI wrote:
> My wife asked me, "how sure are you that this was done correctly"? The
> answer was "about 95%". By implication I was saying that my uncertainty
> was only 5%. There is an interesting assymetry here. The difference
> between being 95 versus 99 percent sure is about 4% while the difference
> between being 5 versus 1 percent uncertain is 500%.
>
> Nothing profound, just an observation. Which way of answering is better,
> in terms of certainty or in terms of uncertainty?
>                                                      Ludwik Kowalski

On the other hand, there are parallels in physical measurements:
A beam of light reflects off a glass surface with a reflectance R and is
transmitted into the glass with a transmittance T so that R + T = 1. 
(Each of R and T are fractions of incident power.)  
Now if R is measured as .1 with a deviation of .01, this gives a
relative deviation of 10%.
The same data gives a measured T value of .9 with a deviation of .01 and
a relative deviation close to 1%.
(This is an instance of how the same data can be given different "spins"
for various purposes in politics, marketing, science, etc.)
-- 
Bob Sciamanda		sciamanda@edinboro.edu
Dept of Physics		sciamanda@worldnet.att.net
Edinboro Univ of PA	http://www.edinboro.edu/~sciamanda/home.html
Edinboro, PA		(814)838-7185