participants

• target population= the group of individuals a researcher is interested in
• sampling frame= the smaller group from the target population that is used to select the sample
• sample group= the participants used
• sampling techniques; opportunity, self-selected, systematic , random , snowball , stratified and quota
• opportunity= choosing people who are available at the time
• strengths of oppourtunity:

  • quicker and easier
  • appropriate when sampling frame is unknown
• weaknesses of oppourtunity:

  • likely a biased sample
  • increased chance of researcher bias
• self-selected= ppts volenteer to take part
• strengths of self selcted:

  • seen as more ethical
  • quicker and easier
• weakness of self selected:

  • prone to volenteer bias
  • more likely to have demand characteristics
• systematic= using a pre-determined system to select every nth ppt from target population
• strengths of systematic:

  • less chance of bias
  • quicker then stratified
• weakness of systematic:

  • may result in a "freak" sample
  • not practical when the sampling frame is unknown
• random= list of all target population and put their names in a hat and pick them at random
• strength of random:

  • unbiased
  • less chance of researcher bias
• weakness of random:

  • time consuming
  • may still get "freak" sample
• snowball= find one or a few ppts and they recruit further ppts
• strenghts of snowball:

  • gain access to difficult to reach ppts
  • appropriate when sampling frame is unknown
• weakness of snowball:

  • unlikely to be representative= difficult to generalise
  • more time consuming
• stratified=subgroups within the target population are identified and ppts are randomly selected at the proportion they appear in the target pop
• strengths of stratified:

  • most representative
  • less chance of researcher bias
• weakness of stratified:

  • very time consuming
  • will be some bias
• quota= subgroups are identified with the target population and ppts are gained from pre-set numbers from each group using a non-random technique
• strength of quota:

  • most representative
  • quicker then stratified
• weakness of quota:

  • very time consuming
  • will still contain some researcher bias