Uncertainty Module 1.1

This module aims to teach the basics statistical concepts that are commonly used in describing experimental data and results in analytical chemistry. You've probably met many of these concepts already; the module is structured to account for this. Try jumping straight to the practice/self-assessment questions on Alchemy before returning here to brush up as needed.

In this module and following ones, we will use a fictional example about checking the quality of a drinking water source. Taconite Lake is the source of drinking water for a town in northern Mexico. It is located downstream from a newly opened iron-ore mine, and the lake water must be regularly tested to determine if heavy metals are making their way into the lake. If the concentration of heavy metals in the water gets too high, the water will be unsafe for consumption.

Water flowing from the mine area may become contaminated with lead (among other possibilities) because lead is a minor component of the iron-containing rocks that are being mined. Lead contamination of drinking water is a serious problem, as the lead slows physical and mental growth in children and other serious conditions for adults. The maximum acceptable concentration of lead in drinking water is 10.0 µg/L. To be considered safe for consumption, the measured lead concentration of the water must be below this value. Each time a sample of water is tested, the result is a determination of the lead concentration.

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