RE: what good is "percentage error"?

[George Spagna <gspagna@rmc.edu>]

At 11:41 AM 5/12/97 EDT, Ludwik Kowalski wrote:
> It is better to say "I am off 5%" than "I am off 2 cm". What is wrong with
> using this percentage error indicator for a single evaluation, as long as
> you say this clearly. Yes, it does not say a lot but it does say something.

I don't think the original question was about the efficacy of using
percentages vs. units when reporting uncertainties.  The issue is whether
the uncertainty is measured relative to the experiment, or relative to some
"right" answer.  

The "formula" quoted in the original post is clearly telling the students
that the purpose of scientific experiment and measurement is to get the
right answer, reinforcing the notion that the content of our discipline is
one of memorizable facts rather than a process for examining the world
around us.

George Spagna           **********************************************
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