Practical Data Analysis with JMP®

Representativeness and Sampling

If we plan to draw general conclusions about a population or process from one sample, it's important that we can reasonably expect the sample to represent the population. Whenever we rely on sample information, we run the risk that the sample could misrepresent the population (in general, we call this sampling error). Statisticians have several standard methods for choosing a sample. No one method can guarantee that a particular sample accurately represents the population, but some methods carry smaller risks of sampling error than others. What's more, some methods have predictable risks of a sampling error while others do not. As you'll see later in the book, if we can predict the extent of the risk, then we ...