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An in-class experiment to illustrate the importance of sampling techniques and statistical analysis of data to quantitative analysis students

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JudithAnn R. Hartman

Department of Chemistry, United States Naval Academy, Annapolis, MD 21402-5026

Daniel W. Bacon

Department of Chemistry, Kutztown University, Kutztown, PA 19530

Wayne C. Wolsey

Department of Chemistry, Macalester College, St. Paul, MN 55105-1899

J. Chem. Educ., 2000, 77 (8), p 1017

DOI: 10.1021/ed077p1017

Publication Date (Web): August 1, 2000

Section:

History, Education, and Documentation

Abstract

A simple in-class experiment designed to show the importance of sampling protocol and the use of statistics in data analyses is described. Two samples are presented to the class, an unmixed core sample and a mixed core sample. The samples contain equal amounts of two colors of otherwise identical candies. The candies in the unmixed sample are in two separate layers in a tall opaque cup and the candies in the mixed sample are in a paper bag. The class is divided into two groups, each of which repeatedly analyzes one of the samples by each person drawing out one candy. The results from each analysis (as a percentage of one of the colors) are tabulated on the blackboard and used to discuss what constitutes a good sampling protocol and a good sample. In addition, the results are used throughout the entire unit on statistics to demonstrate many calculations such as pooling data, comparison of means, confidence limits, and the use of Student's t-test. This demonstration has proved to be useful for engaging the interest of most students in sampling and statistics, and it is a particularly effective means of teaching active learners the very formalistic subject of statistics.

Keywords (Audience):

Second-Year Undergraduate

Keywords (Domain):

Analytical Chemistry

Keywords (Feature):

Tested Demonstrations

Keywords (Pedagogy):

Problem Solving / Decision Making

Keywords (Subject):

Quantitative Analysis

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This article has been cited by 6 ACS Journal articles (5 most recent appear below).

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Journal of Chemical Education2004 81 (11), 1641
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Titrimetric Determination of Carbon Dioxide in a Heterogeneous Sample ("Pop Rocks")
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Journal of Chemical Education2003 80 (5), 552
- Titrimetric Determination of Carbon Dioxide in a Heterogeneous Sample ("Pop Rocks")
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  Journal of Chemical Education2003 80 (5), 552
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