sampling techniques

• a target population is the wider group of people from whom a sample is drawn
• a sample is a smaller group of people selected from a larger population for the purposes of that study
• five listed sampling techniques

  1. opportunity sampling
  2. volunteer sampling
  3. systematic sampling
  4. random sampling
  5. stratified sampling
• opportunity sample:

  asking people nearby if they would like to participate

  strengths:

  convenience

  limitations:

  bias

  might not be representative of target pop
• random sample:

  ensures each participant has an equal chance of being picked e.g. 'name out of a hat' of all the names in a target pop

  strength:

  eliminates bias

  highly representative

  limits:

  difficult to make a list

  costly
• stratified sample:

  dividing a population into subgroups/strata and then randomly selecting from each subgroup

  strengths:

  reduces bias

  highly representative of target pop

  limits:

  difficult to classify subgroups

  overlapping strata
• systematic sample:

  variation of random sampling, a propability sampling method used to select participants from a population at a regular interval

  strengths:

  reduces bias

  highly representative

  limits:

  extremely time consuming
• volunteer sample:

  participants choose to be a part of the study by responding to an advertisement

  strengths:

  ethical as consent is given by volunteering

  random (to some extent)

  limits:

  people with certain personality types are likely to volunteer, meaning maybe not representative
• random sampling is the most representative method, whilst opportunity and volunteer samping are the least representative