Sampling

• Target population refers to the large group of indiviuals that a researcher is interested in.
• A good sample should be representative of the target population so that it can be generalisable.
• Opportunity Sampling - researchers select anyone who happens to be willing and available to take part in the study.
• Opportunity Sampling Evaluation

  • Very convenient and Economical
  • Unrepresentative and may have research bias
• Volunteer Sample involves participants selecting themselves to be part of the sample.
• Volunteer Sample Evaluation

  • Minimal effort and not time consuming
  • Participant bias
• Random Sample - all members of the target population have an equal chance of being selected.
• Systematic sampling - every nth member of the target population is selected, for example every 3rd house on the street.
• Systematic Sampling Evaluation

  • Free from research bias and fairly representative.
  • Time consuming and some participants may refuse to take part.
• Stratified Sampling - the sample reflects the proportions of people in certain subgroups within the target population.
• Stratified Sampling Evaluation

  • Free from researcher bias, produces representative data that is generalisable.
  • Stratifying cannot represent all of the ways in which people are different therefore representing the target population is not possible.