Chapter 11 - SAMPLING

Abstract

Statistical sampling is the process by which a portion of the whole population or universe is selected for examination with the intent to generalize from that sample to the entire population. Samples are selected because data obtained in through sampling can be collected quickly when needed and at a lower cost than collecting data on every element of the subject under study. The chapter discusses simple random sampling, systematic sampling, stratified sampling, cluster sampling, and disproportionate sampling. It also discusses the process of weighting sample results to adjust for disproportionate sampling and varying response rates and to produce population estimates. Simple random sampling approach involves selecting elements or members from a group or population at random. Systematic sampling is used for selecting elements from a list. The members of the group are listed in some type of actual or implied order and a given number of members are selected from the group by picking every nth item from the list, with the starting point selected randomly.