Re: simple maths question

[aah@nofs.navy.mil]

I am not sure I understand John's latest questions, but
I'll try.  If I answer the wrong question, you need to
restate.

>And if standard deviations were not quoted for measures you would
>generate a standard deviation with respect to the measures themselves
>(for the measures themselves), or is that meaningless?
  You can do this, but the answer is meaningless if what you
are measuring is a variable since the standard deviation would
then include the star's variation in addition to any measurement error.
So there are at least two parts to the puzzle:  how well you
can measure something, and any variation intrinsic to the object itself.
When reporting measurements, the error attached to any single measurement
reflects the quality of that single measurement, and usually includes
error sources such as Poisson noise and errors in your comparison stars.

>I've always wondered, because the sheer fact of standard deviation being
>available for each measure makes the overall value far smaller than if
>there weren't any.
  This statement doesn't make any sense to me.  Try again!
Arne