Sampling:

• What are the 5 types of sampling?

  1. Random sampling
  2. Opportunity sampling
  3. Volunteer sampling
  4. Systematic sampling
  5. Stratified sampling
• Random sampling:

  1. Identify all members of the target population, e.g. identify all names of children in a school
  2. Put all of those names on identical pieces of paper
  3. Draw blind from a hat
  4. Allocate participants to conditions
• What are some strengths of random sampling?

  • It is likely to produce a representative sample
  • It is likely to safely generalise conclusions about the target population
  • Likely makes high population validity
• Opportunity sampling:

  1. Researcher approaches potential participants and asks if they will take part
  2. The ones who agree to take part form the sample
• Volunteer Sampling:

  1. Place an advert in a local newspaper or on a notice board. Potential participants can then approach the researcher
  2. Those who see the advert and wish to take part will approach the researcher
• What are some weaknesses of opportunity and volunteer sampling?

  • It is likely to produce an un-representative sample
  • Likely makes low population validity
• Stratified sampling:

  1. identify all members of the target population
  2. Identify the different sub-groups relevant to the study (in the target population)
  3. Randomly select (from each category) in the same proportions s they exist in the target population
• Systematic sampling:

  1. Identify all members of target population
  2. Determine the nth number (to do this you need to put the participants in a list and determine the nth number by deviding target population by the amount you want