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The Chemical Educator

ISSN: 1430-4171 (electronic version)

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Abstract Volume 12 Issue 4 (2007) pp 260-262

The Statistics of Coffee: 1. Evaluation of Trace Metals for Establishing a Coffee’s Country of Origin Based on Mean Comparison

Michael R. Columbia

Chemistry Department, Indiana University Purdue University Fort Wayne, Fort Wayne, IN 46805-1499,
Received September 10, 2006. Accepted June 24, 2006.

Published online: 4 August 2007

Abstract. The determination of significant differences between two populations based on comparison of their mean values is a very important tool provided analytical chemists by Gaussian statistics. One important real-world application of this technique of mean comparison is determining the origin of agricultural commodities based on differences in the trace metal content. Variations in the amounts of certain trace metals can arise from divergent soil and weather conditions and can be used like a fingerprint to distinguish an agricultural product of one country from the same product grown in another country. The experiment described here guides students through the determination of the content of two trace metals (manganese and copper) in green coffee beans from two countries (Costa Rica and Colombia), then asks them to evaluate each metal as a possible fingerprint to distinguish the origin of the coffee based on the mean comparison technique.

Key Words: Laboratories and Demonstrations; analytic chemistry; statistics

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Article in PDF format (82 KB) HTML format page numbers updated 9/15/07

Issue date: August 4, 2007

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