Sampling Flashcards
Population
a group of people who are the focus of the researchers interest, from which a smaller sample is drawn
Sample
a group of people who take part in research investigation. the sample is drawn from a population and is presumed to be representative of that population
sampling techniques
method is used to select people from the population
bias
in the context of sampling, when certain groups may beaver and under-represented within the sample selected.
limits the extent to which generalisations can be made to the target population
generalisation
the extent to which findings and conclusions from a particular investigation can be broadly applied to the population. This is made possible if the sample of participants is representative of the population
Random sample
all members of the target population have an equal chance of being selected
- complete a list of all members of the target population
- all names on the list are assigned a number
- sample is generated through the use of some lottery method (computer-based randomiser or picking numbers from a hat)
Systematic sample
every nth member of the target population is selected
- a sampling frame is produced, which is a list of people in the target population organised into for instance alphabetical order
- a sampling system is nominated (every nth) or this interval may be determined randomly to reduce bias
- researcher then works through the sampling frame until the sample is complete
Stratified sample
composition of the sample reflects the proportions of people in certain sub-groups (strata) within the target population or the wider population
- researcher identifies the different strata that make up the population
- the proportions needed for the sample to be representative are worked out.
- the participants that make up each stratum are selected using random sampling.
Opportunity sample
researchers may just ask people who are available and willing
takes the chance to ask whoever is around at the time of their study
Volunteer sample
participants selecting themselves to be part of the sample
- researcher may place an advert in a newspaper or on a common room notice board.