A novel laboratory activity in sampling statistics, suitable for students in a quantitative analysis course, is described. In this activity, students measure the percentage of iron in a commercial lawn fertilizer by simple sorting and weighing. The pooled class data is used to determine the percent relative standard deviation due to sampling error, and this is compared to a theoretical model based on sampling statistics. The experiment is simple to perform, but significant and meaningful data is generated to help reinforce the most important ideas related to sampling theory. The use of a real-world sample is particularly intriguing and meaningful to the students. Results from two semesters have consistently demonstrated both the validity and limitations of the two-component sampling theory used in the analysis.
Supplement
Instructions for the students and notes for the instructor are available.
Our Secondary School editors work hard to distill all the JCE materials to produce a fraction of particular interest to high school teachers. We call it CLIC.
In recent years we have worked hard to better match our advertisers with our readers. When shopping for chemistry education materials, visit our advertisers' WWW sites first.
Take JCE along on your outreach missions. Copies of the Journal, guest access to JCE Online, our publications catalog, and more are available for your participants.