ABSTRACT
This chapter introduces the basic principles of sampling and some of the main practical techniques that are employed in the biological sciences. It describes the main sampling techniques utilised by biologists that minimise the potential for sampling bias. Both simple random and stratified random sampling techniques, as their names suggest, rely on random selection procedures. In these two methods, each member of the population or stratum has the same probability of being selected as all the others in the population or stratum. Systematic sampling, on the other hand, is not truly random although it does include an element of random selection. The chapter describes the combination of the key elements of sampling methodology and the principles of probability provide the basic tools to perform biological investigations. It outlines some of the techniques that enable one to determine the size of the sample that they need to gather in order to satisfy the objectives of an investigation.
