Samples and sampling

• Sampling frame


  • A list of people from which the sample is selected. (E.g. A register in school or college.)
  • It should list everyone in the survey population that the sociologist is interested in but isn’t always possible.
• Random sampling

  • The sample is selected from the sample frame by chance (e.g. Random name chooser.)
  • If a random sample is big enough, it should be representative although many are not.
• Systematic sampling

  • Picking every nth person from your sample frame.
• Stratified sampling

  • Divides population into groups called ‘strata’ by a characteristic. (E.g. population separated by gender).
  • A sample is taken from these strata using either random, systematic, or convenience sampling.
• Convenience sampling

  • Also known as opportunity sampling > method that selects participants from the population - members who are conventionally available to participate in study.
• Quota sampling

  • The population is stratified.
  • Each researcher is given a quota to fill, linked to a characteristic.
• Snowball sampling

  • Make contact with one initial participant.
  • That participant then puts the researcher in contact with other participants.
  • Useful for studying difficult to access groups like drug addicts.