sampling Flashcards
what is a population?
The population is the group of people from whom the sample is drawn.
what is a representative sample?
If your sample is representative then you can generalise the results of your study to the wider population.
what is opportunity sampling?
taking the sample from people who are available at the time the study is carried out and fit the criteria you are looking for.
what is random sampling?
every member of the population has an equal chance of being chosen.
- This involves identifying everyone in the target population and then selecting the number of participants you need in a way that gives everyone in the population an equal chance of being picked.
what is stratified sampling?
Stratified sampling involves classifying the
population into categories and then choosing a sample that consists of participants from each category in the same proportions as they are in the population.
what is self-selected sampling?
Self-selected sampling (or volunteer sampling) consists of participants becoming part of a study because they volunteer when asked or in response to an advert.
what is systematic sampling?
Participants are chosen mathematically, choosing every nth person.
strengths of systematic sampling
It avoids bias as once the researcher has decided what number they are going to use for the selection, they have no control over who is being selected.
The law of probability says that the researcher will normally get a representative sample.
weaknesses of systematic sampling
There is a small chance of a ‘freak’ sample that would not be representative.
It is not completely objective because the researcher may decide on how people are listed before the selection and on what number to use for the system.
