sampling

• population


  group of people who are the focus of the researcher's interests, smaller sample can be drawn
• random sample 


  all members of target population have an equal chance of being selected
• systematic sample


  when every nth member of target population is selected
• stratified sample


  composition of the sample reflects the proportions of people in certain sub-groups within target population
• opportunity sample


  select anyone who happens to be willing and available
• volunteer sample


  select themselves to be part of sample
• random sample (evaluation) 


  strength:

  • no researcher bias

  weakness:

  • time-consuming
  • unrepresentative sample
  • participants may refuse to take part
• systematic sample (evaluation)

  strength:

  • avoids researcher bias

  weakness:

  • unrepresentative
• stratified sample (evaluation)


  strength:

  • no researcher bias
  • representative sample

  weakness:

  • cannot reflect all the ways that people are different
• opportunity sample (evaluation)


  strength:

  • convenient- no time or effort and cheap

  weakness

  • unrepresentative
  • bias- researcher could choose people they like the look of
• volunteer sample (evaluation)


  strength

  • easy-minimum effort

  weakness

  • asking for people may attract a certain type of people