Sampling Flashcards
What does sampling involve
used to obtain Pp who will take part in research
it is taken from the population that is relevant to the research topic; may be taken from a target population in order to generalise
What are the different sampling techniques
Stratified
Random
Volunteer
Opportunistic
Systematic
What is stratified sampling
it is a proportional representation of the target population
How do you obtain a stratified sample
divide the amount by the total and then times by your sample size
Evaluate stratified sampling
it is representative of the target population so can therefore be generalised easily; the selection is also unbiased as it is based on the subgroups in society
HOWEVER
it can be very time consuming and difficult to select appropriate categories
What is random sampling
when every member of the target population has an equal chance of being selected
could be done by names in a hat or computer generated
Evaluate random sampling
it is quick and easy to conduct and the researcher does not need to know much information about Pp beforehand; is it an unbiased selection as the researcher cannot control who is chosen, making the results more generalisable
HOWEVER
the sample needs to be drawn from a large population to be unbiased as all names may end up being male for example so in this case stratified sampling may be better
What is opportunistic sampling
Pp are selected from whoever is available at the time of the study (walkers on the street)
Evaluate opportunistic sampling
it is quick and easy as it is convenient for the researcher and no sampling time frame is required
HOWEVER
the sample is not representative as it is drawn from a small section of the community which reduced external validity; it is also likely to be biased as the choice of person relies on the judgment of the researcher
What is volunteer sampling
Pp select themselves to be in a study
(e.g newspaper advert)
Evaluate volunteer sampling
it is easy to obtain and requires little effort; it accesses a wide variety of people who are motivated to take part
HOWEVER
it can lead to volunteer bias; people who volunteer tend to be more highly motivated and have certain personality traits in common meaning the sample is not representative/cannot be generalised to a population which reduces external validity
Volunteers are often eager to please which causes demand characteristics
What is systematic sampling
selecting every nth person from a list; used a predetermined system
Evaluate systematic sampling
it is an unbiased selection so can be generalised to the target population
HOWEVER
it is not actually random unless you select a person randomly to begin the counting from
