sampling Flashcards
what is sampling?
- selecting participants from a target population (the subgroup to be studied, to which the results will be generalised)
random sampling
- every member of the population has an equal chance of being selected
- e.g. via pulling names from a hat or using a random name/number generator
evaluate random sampling
+ free from researcher bias as they have no input into who is chosen
– difficult and time-consuming, and if people chosen don’t want to take part it becomes more like volunteer sampling
systematic sampling
- a predetermined system is used to select participants
- e.g. every 5th person is chosen
evaluate systematic sampling
+ free from researcher bias as they don’t select participants by choice
– may not be fully unbiased - every nth person may have a specific characteristic making the sample not representative
stratified sampling
- identify subgroups in a population
- people are chosen from each group in proportion to their occurrence in the population
evaluate stratified sampling
+ mostly free from researcher bias, the sample is randomly generated once subgroups are identified
– difficult and time consuming
opportunity sampling
selecting anyone who is willing and available to take part
evaluate opportunity sampling
+ convenient, quick and easy
– issues of bias as the sample is often from a specific area, unlikely to be overly representative and the researcher has control over who they approach
volunteer sampling
participants self select to take part by volunteering when asked or responding to an advert
evaluate volunteer sampling
+ requires minimal effort and input from the researcher, so is quicker and easier
– issues of bias, usually it’s a certain type of person who is likely to take part in research, not representative
