Stratification implies layers or differences. A quick test for soil composition is to place a sample of soil with water in a clear jar and give it a shake. The sand, silt and loam will settle at different rates and create a layered appearance within the jar over time. The height of each layer provides information about the proportion of each type of soil within the sample.

Stratification as one of the seven basic quality tools (some lists use a run chart or flowchart instead) the idea of layers or differences still applies. The idea is to identify potentially meaning differences within a sample set. Continue reading →