Sampling Flashcards
What are the 4 sampling methods?
Random, opportunity, stratified, volunteer
What is random sampling?
Random sampling involves selecting members of the target population in a random way. This can be done using a computerised random number generator, or even by simply drawing names out of a hat.
What is the advantage of random sampling?
Every member of the target population has an equal chance of selection, and that there is no experimenter bias in who takes part.
What is the disadvantage of random sampling?
Even a random sample may not truly represent the target population (e.g. a random sample of 12 people may by chance all be the same gender).
What is opportunity sampling?
An opportunity sample is one that happens to already exist somewhere. An example could be year 12 students studying psychology as a ready-made group of these will exist in most sixth forms. Another example might be children already at a day care centre
What is the advantage of opportunity sampling?
It is quick and easy as the sample already exists.
What is the disadvantage of opportunity sampling?
The opportunity sample is biased because the members of it have self selected and are all similar in at least one way, therefore any results will only be truly generalisable to that specific group of people.
What is stratified sampling?
The researcher identifies the different types of people that make up the target population and works out the proportions needed for the sample to be representative and samples each group individually.
What is the advantage of stratified sampling?
The sample should be highly representative of the target population and therefore we can generalize from the results obtained.
What is the disadvantage of stratified sampling?
Time consuming and difficult to do
What is volunteer sampling?
Volunteer samples are ones in which the participants have put themselves forward as research candidates. Researchers obtain volunteer samples by advertising on posters or in newspapers.
What is the advantage of volunteer sampling?
Participants will all be happy and willing to participate, and they will not feel coerced in any way.
What is the disadvantage of volunteer sampling?
It will be biased towards a certain type of person as only people with a personal interest in the research topic will volunteer. The sample will not therefore be truly representative of the target population.
