sampling Flashcards
define ‘population’
the group of individuals that the researcher is interested in studying e.g teenagers
define a ‘sample’
a smaller group selected from the intended population to be studied
what is random sampling?
where each member of the population has an equal chance of being selected. this could be done as ‘names in a hat’ or via a random computer generator
what is systematic sampling?
involves taking every ‘nth’ person from a list to create a sample (e.g every 5th person)
what is stratified sampling?
involves dividing the population into characteristics that are important for the research (e.g age) and then the population is randomly sampled within each category
what is opportunity sampling?
involves selecting participants who are AVAILABLE and WILLING to take part
what is volunteer sampling?
involves the researcher placing an advert which gives details of the study, and people will volunteer if interested
advantages/disadvantages of random sampling
advantages:
there is a reasonable chance of achieving a representative sample
free from researcher bias
disadvantages:
small minority groups could effect results, even with a random sample
it can be impractical-groups may be to big
advantages/disadvantages of systematic sampling
advantages:
involves minimal researcher bias (investigator effects)
disadvantages:
bias is still a possibility if the list is not randomised
advantages/disadvantages of stratified sampling
advantages:
avoids the problem of misrepresentation
disadvantages:
requires more time and planning
advantages/disadvantages of opportunity sampling
advantages:
it is easy, convenient and inexpensive
disadvantages:
researcher bias is possible
may not be representative
advantages/disadvantages of volunteer sampling
advantages:
achieves a larger sample size-reaches a wider audience
easier for the researcher
minimises investigator effects
disadvantages:
those responding may display similar characteristics (volunteer bias)
