Sampling

• Sampling:

  • A sample is the participants you select from a target population
• Volunteer Sample:

  • Where participants pick themselves through newspaper adverts or online to take part in the research.
• Opportunity Sample:

  • This uses people who are available at the time the study takes place.
  • Strength:
  • Time saving
  • Less expensive.
  • Weakness:
  • Not representative so lacks generalisability.
  • Researcher bias is presented as they can pick who is selected.
• Random Sampling:

  • When every person in the target population has an equal chance of being selected.
  • Strength:
  • No researcher bias as the researcher does not choose who is picked.
  • Weakness:
  • Time consuming as you need to have a list of members of the population + contacting them takes time.
  • Volunteer bias as participants can refuse to take part which can lead to an unrepresentative sample.
• Systematic Sampling:

  • When a system is used to select participants.
  • Strength:
  • Avoids researcher bias and usually is representative of the population.
  • Weakness:
  • Not truly unbiased unless you use a random number generator to start the systematic sample.
• Stratified Sampling:

  • When you identify subgroups and select participants in the proportion with their occurrence.
  • Strength:
  • No researcher bias.
  • Representative data due to proportional strata.
  • Weakness:
  • Time consuming to identify strata and contact people from each.
  • Not complete representation as the identified strata cannot reflect all the differences between the wider population.