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Re: what good is "percentage error"?



I find that the source of the students reliance seems to be the
chemistry courses here. They are taught to calculate this every time, and
to my horror, are graded on their "percent error"; i.e. 1%=A, 2%=B, etc.
Mike Monce
Connecticut College


In the quantitative analysis course, students are taught to analyze samples
with accuracy in the parts per thousand range. Students often analyze a sample
whose composition is accurately known and supplied by a company specializing in
supplying such.

IF a given sample is capable of being analyzed to an uncertainty of 2 parts per
thousand, then it is expected that the student perform at that level for the A
grade. The B, C, etc. grades are assigned to increasing deviations from the
"true" or accepted value for that sample.

I'm not certain of the origin of your "horror", but the grade is designed to
reflect the accuracy with which the analysis is performed in a course which is
designed to teach quantitative methods.

Ciao,



:-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-)
:-) :-)
:-) Frank M. Lanzafame Department of Chemistry :-)
:-) Monroe Community College 1000 East Henrietta Rd. :-)
:-) Rochester, NY 14623 (716) 292-2396 :-)
:-) Internet: flanzafame@monroecc.edu :-)
:-) :-)
:-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-)