ABSTRACT
This chapter describes the methods by which they can be applied to problems where one needs to compare two samples of measurements. It details the different types of two-sample comparisons that one might encounter. Two-sample comparisons can be divided into those relating to independent or unpaired samples and those that are concerned with dependent or paired samples. Comparisons of this type are so common in biology that this ability to discriminate is absolutely essential. The chapter illustrates the difference using the pulse rate investigation. It deals with comparisons of independent groups and those involving paired data, and considers the nature of the data involved in the investigation in order to enable them to choose between tests based upon the normal distribution and alternative, non-parametric tests. The chapter presents the alternative tests that are employed when the data do not conform to a normal distribution.
