sampling

• state all the different types of sampling

  • random
  • systematic
  • stratified
  • volunteer
  • oppourtunity
• what are the advantages and disadvantages of systematic sampling?

  ADVANTAGES:

  • unbiased- objective system

  DISADVANTAGES:

  • not truly unbiased unless you have a random method of where to start with members of the population on the list
• what are the advantages and disadvantages of opportunity sampling?

  ADVANTAGES:

  • Quick
  • easy
  • not time consuming

  DISADVANTAGES:

  • biased as you are picking people most easily available to you, depends on who's around at the time
  • sample drawn from a small part of the population
  • not representative sample- can't generalise findings to other groups of people therefore
• what are the advantages and disadvantages of volunteer sampling?

  ADVANTAGES:

  • access to a large variety of people- more representative and less biased

  DISADVANTAGES:

  participants may show volunteer bias eg-

  • biased in other ways because participants more likely to be motivated
  • participants may be more likely to have time on their hands
  • pps may be more educated
  • more broke and needing money offered for participation
• what are the advantages and disadvantages of random sampling?

  ADVANTAGES:

  • representative- all members within the population have an equal chance of being selected
  • unbiased as participants selected using objective system

  DISADVANTAGES:

  • could end up with potentially biased sample
  • may not be possible to contact those selected
  • need to obtain a list of all the members of a population
• how can we conduct a stratified sample?

  • identify subgroups/strata within a population
  • participants obtained from each of the strata according to their occurrence in the population
  • selection from the strata is done using a random sampling technique
  • allows samples to be representative