Sampling

• Random sampling

  Where every member of a population has an equal chance of being selected for a given investigation e.g. putting names in a at and drawing them out
• Systematic sampling

  Participants are selected from the target population at regular intervals until the size of the sample is reached e.g. selecting every third pupil from the register
• Stratified sampling

  Researcher divides the population into stratas (subgroups), then randomly selects pps proportionally from each strata e.g. teacher divides her class into different races, hair colour and eye colour then randomly selects students from each group
• Opportunity sampling

  Taking samples from people who are willing and available at the time the study is carried out and fit the criteria you are looking for e.g. approaching children at school during break time
• Volunteer sampling

  Consists of pps becoming part of a study because they volunteer when asked or in response to an advert or invitation e.g. Zimbardo’s study
• Population - a large group. of individuals the researchers says may be involved in the study
• Target population - a subset of the general population
• Sample - a subgroup of the target population who take part in the study