Question : Accuracy of data

Hi

Again this question is about wanting to know the right way to describe a mathematical relationship.

Returning to Beers Law A =ecl, if you had the absortion of a molecule at a particular concentration you could work out e (should be epsilon, the molar absorption coefficient) if you know l (pathelength). However another way would be to obtain A at a range of different concentrations and plot a graph of A vs concentration and work out e from teh gradient.

The latter method is more superior but I'm not sure I know how to put it into words why. The first method works out e from a single value and so, and this is how I don't know how to say it, is totally 'vulnerable' to error. In the second method you can see if there are any erroneous data points from your graph (it should give a straight line) so you have opportunity to correct for error. Also the second method is more representative of a range of data but I don't know how to put that into words either.

thanks

Answer : Accuracy of data

":how I don't know how to say it, is totally 'vulnerable' to error. In the second method you can see if there are any erroneous data points from your graph (it should give a straight line) so you have opportunity to correct for error. Also the second method is more representative of a range of data but I don't know how to put that into words either."
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There are several comments and ways of putting your ideas.
"how I don't know how to say it, is totally 'vulnerable' to error."
ie IT is less reliable
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" Also the second method is more representative of a range of data but I don't know how to put that into words either."
ie it is more reliable or has a smaller probable error.
NOTE: You must be VERY careful NOT to "correct" a data point JUST because it is not on an expected straight line.(People have missed a chance to get the Nobel prize because of this error.)