ABSTRACT
Introduction Sometimes researchers, having obtained a score for a person or a sample, wish to know how common such a score is within a population. In addition, researchers want to know whether a measure they have taken from a person, or a sample of people, is statistically different from the equivalent measure from a population. This chapter introduces a family of statistical tests-z-tests-which allow both these sorts of questions to be answered. In addition, it introduces a related family of tests-t-tests-which can be applied in some circumstances when there is insufficient information to use a z-test.
