Question: Explain the different sampling techniques used by marketing researchers. Samples can be categorized as either probability samples or nonprobability samples. A probability sample is one in which every member of the population has a known chance of being selected. Probability samples include simple random samples, in which every item in the relevant universe has an equal opportunity to be selected; stratified samples, in which randomly selected subsamples of different groups are represented in the total sample; and cluster samples, in which geographic areas are selected from which respondents are drawn. A nonprobability sample is arbitrary and does not allow application of standard statistical tests. Nonprobability sampling techniques include convenience samples, in which readily available respondents are picked, and quota samples, divided so that different segments or groups are represented in the total sample.