Adam,
OK, seems like you are going with "it's always statistical error we just
don't yet know what it is" option.
Ed.
On Tue, 2013-03-12 at 16:15 +0000, Adam Ralph wrote:
> Hi Ed,
>
>
> You can have both types of error in a single experiment, however
> you cannot determine
> statistical (precision or as Ian says uncontrollable) error with one
> experiment. The manufacturer
> will usually give some specs on the pipette, 6ul +/- 1ul. In order to
> verify the specs
> you would need to perform many pipetting experiments. But even if the
> manufacturer does not give
> any specs you still know that the pipette is not perfect and there
> will be a statistical error, you
> just do not know what it is.
>
>
> In theory, accuracy or bias could be determined with one
> experiment. Lets say you thought
> you had a 6ul pipette but actually it was a 12ul pipette. If you then
> compare the 'new' pipette
> against a standard you could tell if it was inaccurate. Of course
> normally you would repeat
> this experiment as well because of statistical error. If detected bias
> can be removed. Systematic
> error may not be so easily detected. What if the standard is also
> biased.
>
>
> Adam
>
>
>
>
> > One can say it's inaccuracy when it is not estimated and imprecision
> > when it is. Or one can accept Ian's suggestion and notice that
> there is
> > no fundamental difference between things you can control and things
> you
> > can potentially control.
--
Edwin Pozharski, PhD, Assistant Professor
University of Maryland, Baltimore
----------------------------------------------
When the Way is forgotten duty and justice appear;
Then knowledge and wisdom are born along with hypocrisy.
When harmonious relationships dissolve then respect and devotion arise;
When a nation falls to chaos then loyalty and patriotism are born.
------------------------------ / Lao Tse /
|