Sampling Flashcards
Define a population
- the large group of individuals a researcher is interested in studying
- for example women in their thirties
- this is their target population
What is a sample?
- A smaller group representative of a larger population
What are the different sampling techniques?
- Random sampling
- Opportunity sampling
- Systematic sampling
- Stratified sampling
- Volunteer sampling
What is a random sample?
- Where all participants have an equal chance of being selected
- this can be done with a random name generator or the lottery method
What is a systematic sample?
- A system where every nth member of a target population is selected from the sampling frame
sampling frame = the list of the target population organised in alphabetical order for instance
What is a stratified sample?
- a sophisticated form of sampling where the composition of the sample reflects the real proportion of people in the target population
- first u identify the strat (proportions)
- then calculate the required population per strat
What is an opportunity sample?
- Researchers select anyone who is willing and avaliable
What is a volunteer sample?
- participants select themselves to be a part of a sample
- this is usually in response to an advert or newspaper
Evaluate random samples?
- S = no research bias , increasing internal validity
- L = Difficult and time consuming
- some participants may refuse to take part if chosen
- may still end up with an unrepresentative sample
Evaluate systematic sampling
S = avoids researcher bias and usually representative
L = Time consuming and not truly unbiased unless u use a random number generator then use a systematic sample
Evaluate stratified sampling
S = NO research bias and is very representative of to the target population
L = time consuming and difficult
-does not reflect the individual differences in people
Evaluate opportunity sampling
S = Easy and convenient, less costly
L = the sample may be unrepresentative as it is drawn from a very specific area, reducing generalisability
- research bias
Evaluate volunteer samples
S= minimal effort, less time consuming
- participants will be more engaged
L = volunteer bias, this may attract a certain profile of people who may be money motivated or not take the study seriously