An experiment is described which uses a real-world sample of lawn fertilizer in a simple exercise to illustrate problems associated with the sampling step of a chemical analysis. A mixed-particle fertilizer containing discrete particles of iron oxide (magnetite, Fe[subscript 3]O[subscript 4]) mixed with other particles provides an excellent…

This paper is one of a group that describes the research methodology for an evaluation of individually guided education (IGE) in American elementary schools. Described here are the procedures used to select the sample of schools being studied in the first phase of the evaluation. This phase was a large sample study that used structural equations…