sampling

• what’s a target population 


  a sample of people taken from a larger population, a group of people we wish to make a statement about and draw conclusions
• what’s generalisation 


  the ability to make a statement about the target population in relation to the sample
• what’s random sample


  every person in the target population has an equal chance of being selected
• what are the strengths and weaknesses of random sampling 


  strengths: lack of bias as every person has an equal change of being selected

  weaknesses: this method takes a long time to conduct and a lot to collect

  people may not take part
• what’s an opportunity sample 


  right place at the right time
• strengths and weaknesses of opportunity sampling 


  strengths: easy to conduct as it’s quick and cheap as you select whoes availiable

  weaknesses: unrepresentative of population, participants are from one place so hard to generalise

  • researcher bias, control who takes part
• explain systematic sampling 


  numerical formula is used so researxher needs to complete list of target population then create a formula and apply it until they have a full sample
• strengths and weaknesses of a systematic sample 


  strengths: avoids researcher bias as researcher has no control over who is selected

  weaknesses: may still suffer from bias as tou may end up with all the same gender
• explain stratified samples 


  participants are selected from diff subgroups within the target population in proportion to subgroups overall frequency
• strengths and weaknesses of stratified sampling 


  strengths: most representative of methods, researcher identifies subgroups and ensure that each sub group is represented

  • avoids bias research
  • weaknesses: choice which subgroup is important
  • timely method not all participants agree to participate
  • identified data may not be representative
• what’s volunteer sampling 


  • involves participants selecting themselves to be part of a sample it is known as self selection
  • can be done through putting adverts in newspapers etc
• strengths and weaknesses of volunteer sampling 


  strengths: minimal effect by the researcher

  weaknesses: volunteer bias by asking for volunteers certain people may come forward if the same characteristics