Sampling techniques

• What is the target population in research?

  The people a sample is supposed to represent
• What is a sample in research?

  A group used in research that represents a target population
• What is a sampling technique?

  A method used for gathering the sample
• What are the different sampling techniques mentioned in AQA A Level Psychology?

  • Random
  • Opportunity
  • Systematic
  • Stratified
  • Volunteer
• How does random sampling work?

  Every person in the target population has a chance of being in the sample
• What is an example of random sampling?


  All names of the target population are entered into a computer system to generate a sample list
• What is a potential disadvantage of random sampling?

  The sample generated could be unrepresentative, such as all male
• How does opportunity sampling work?


  The sample consists of people from the target population who are available
• What is an example of opportunity sampling?


  The researcher approaches people and asks them to take part in a study
• What is a disadvantage of opportunity sampling?

  The sample may not be representative of the target population
• What is systematic sampling?

  A predetermined system is used to select participants, such as every fifth person
• What is a potential advantage of systematic sampling?

  It is not affected by researcher bias or choice of participants
• What is a potential disadvantage of systematic sampling?

  The sample may be unrepresentative if every Nth person has similar traits
• What is stratified sampling?


  Subgroups within a population are identified and participants are obtained from each stratum in proportion to the target population
• How would you create a stratified sample from a class of 20 students with 18 males and 2 females?

  A sample of 10 would need to consist of 9 males and 1 female
• What is an advantage of stratified sampling?

  The sample is likely to be representative of the target population
• What is a disadvantage of stratified sampling?

  Ensuring that the subgroups in the target population are all accurately identified is a difficult and time-consuming task
• How does volunteer sampling work?

  Participants self-select to take part in a study by either volunteering when asked or by responding to an advert
• What is an example of volunteer sampling?

  Responding to a poster in a café
• What is an advantage of volunteer sampling?


  It is an easier and quicker method than random or stratified sampling
• What is a disadvantage of volunteer sampling?

  The sample may not be representative, such as only unemployed people volunteering