Sampling

• what are the types of sampling used in experiments?

  • volunteer
  • opportunity
  • random
  • systmatic
  • stratified
• what is 'random sampling'?

  when you generate a sample through a database (lottery method) -> having names on a list and give all a number to generate a sample
• what is a strength of random sampling?

  potentially unbiased (equal chance)
• what is a weakness of random sampling?

  • time sampling
  • costly
  • may be unrepresentative
  • is it possible to create a list
• what is 'opportunity' sampling?

  sample that is available (and willing)
• what is a strength of opportunity sampling?

  • convenient
  • less costly
• what is a weakness of opportunity sampling?

  • researcher bias - researcher has control over who is chosen
  • unrepresentative bias
• what is a 'volunteer' sample?

  a sample that is self selected to partake in the study (willing participants)
• what is a strength of volunteer sampling?

  • easy
  • convenient
  • less time used
  • participants are eager and engaged
• what is a weakness of volunteer sampling?

  • volunteer bias - reducing generalizability
  • participants may be eager and engaged
• what is 'systematic' sampling?

  every sequence/nth number is selected out of a participant list
• what is a strength of systematic sampling?

  it is an objective technique (if the list isn't seen prior to choosing)
• what is a weakness of systematic sampling?

  • time consuming
  • refusal to take part
• what is 'stratified' sampling?

  a sampling technique that reflects the target population, this is seen as the most sophisticated
• what is a strength of stratified sampling?

  • most representative sampling technique - because it is accurate
  • findings may be generalisable
• what is a weakness of stratified sampling?

  • not always completely represented