Taking a sample involves questioning a selection of respondents from a target market. To ensure the results of a sample survey are accurate, the market rsearch process must identify a representative group of customers. If the slection is fair and accurate, the information should be statistically reliable.
Cluster Sampling - Units in the population can often be found in certain geographic groups or "clusters". Therefore instead of sampling in random areas or groups, sampling is carried out in a few areas typical of the market in question.
Convenience sampling - This involves gathering information from anyone available for the interviewer to survey, no matter what his or her background
Judgement Sampling - This involves the interviewer slecting respondents using his or her own judgement that they seemed to be, and looked representative of, the group of customers in the market being researched.
Quota Sampling - Sampling interviewers are given instructions as to the number of people to interview with certain characteristics, such as sex, socioeconomic group or other demographic detail
Simply Random Sampling - allows the researcher to choose the size of the sample required and then to pick the sample on a purely random basis. The sample must be selected in such a way that every item in the sampling frame has an equal chance of being selected. Three types of random: Simple, Sytematic and Stratified
Systematic Sampling - Involves selecting items at regular intervals after choosing a random sampling point. For example, if it is decided to select a sample of 20 people from 1000, then every 50th person should be sampled (1000/20 = 50)