sampling

• What is a population in research methods?

  Large group of people
• Why is a sample used in research?

  It's not possible to include all members
• What does generalisation refer to in research?

  Applying findings from a sample to a population
• What is bias in sampling?

  When certain groups are overrepresented
• What is an opportunity sample?

  • Most available people are selected
  • Quick and convenient method
  • Inevitably biased and unrepresentative
• How is a volunteer sample created?

  Participants choose themselves
• What is a potential issue with volunteer samples?

  They may share certain traits
• What defines a random sample?

  Everyone has an equal chance of selection
• What is a limitation of random sampling?

  Representation is not guaranteed as you need a list and a way to pick randomly
• What is a systematic sample?

  • Participants selected using a set pattern
  • Every nth person from a list is chosen
  • Requires a complete list of the population
• What is a stratified sample based on?

  Frequency in the target population
• How are subgroups identified in stratified sampling?

  By characteristics like gender or age
• What is a strength of stratified sampling?

  It is a representative method
• What is a limitation of stratified sampling?

  Stratification isn't perfect
• what's population validity

  its when the results can be generalised to other people
• if a samples good it will look more like the...

  original population (more representative)
• two pros of volunteer sampling

  1. its easy
  2. can reach lots of people
• con of volunteer sampling

  • may not be very representative of the population
• pro of opportunity sampling

  quick and easy way to get participants
• con of opportunity sampling

  sample won't be very representative of the population
• opportunity vs volunteer sampling

  volunteer- send out an ad and anyone can join

  opportunity- approaching participants
• is opportunity sampling easier than volunteer


  yes
• is volunteer sampling more representative than opportunity 


  yes
• pro of systematic sampling

   

  • it will often lead to a more representative sample than volunteer or opportunity sampling.
• con of systematic sampling

  if there's a pattern the sample may not be representative of the population
• whats random sampling

  picking randomly from a list of the entire population, so that everyone has an equal chance of being a participant
• pro of random sampling

  more likely to be representative
• two most representative samples

  1. opportunity
  2. volunteer
• two least representative groups

  1. random
  2. systematic
• two most difficult groups

  1. random
  2. systematic
• two least difficult groups

  1. volunteer
  2. opportunity
• whats stratified sampling

  sample that has the same proportion of each subgroup, as the total population
• 3 things you should do in stratified sampling

  1. identify important subgroups in population
  2. Identify amount of people from each subgroup that are needed to have same proportion as original population
  3. Randomly sample from each subgroup to get that number
• 2 cons of stratified sampling

  • difficult and time consuming
  • researchers may miss out on important subgroups by mistake
• Pro of stratified sampling

  • Sample will be more representative than all other types
  • Results will generalise to whole population
• whats the most difficult type of sampling

  stratified
• whats the easiest type of sampling

  volunteer
• most studies in psychology use what type of sampling

  volunteer and opportunity sampling because they take less time and effort