Thank you all for the information so far. I have yet to digest it all!
I think I should help with a couple of clarifications: we are looking at
potentially uneven sampling groups (n1 = 10, n2 = 15) and we do have unequal
variances.
The ultimate task at hand is to determine if the concentrations (of a
constituent) from one area are consistent with the concentrations from the
other area. EPA has requested a ttest with diff = StDev.
Kristen Durocher Wandland
ENSR
7041 Old Wake Forest Road
Raleigh, NC 27616
919-872-6600
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