Research Methods: Sampling Methods Flashcards
Define Sampling.
Selecting participants for research.
Define Target Population.
The whole group you are studying e.g. year group at school.
Define Sample.
Those taking part in the research. It should be representative of the target population as a whole.
Define Participant.
An individual in the sample.
What are the 5 Sampling Methods?
Opportunity, Volunteer, Random, Systematic, Stratified
Describe Opportunity Sampling.
How do you go about doing it?
The researcher takes whoever is easily available at the time e.g. uni psychologists frequently sample from their students.
Directly approach people and ask if they are willing to take part.
Describe Volunteer Sampling.
How do you go about doing it?
Asking people to volunteer - individuals determined their own involvement in a study e.g. students in classroom deciding if they want to take part.
Put up posters, newspaper adverts, or direct mail advertising the study and how to get in touch.
Describe Random Sampling.
How do you go about doing it?
Every member of the target population has an equal chance of being selected e.g. pulling names from a hat.
Psychologists can number all the names in the population from which the sample is being taken, then get a computer to randomly select the numbers or just use a hat.
Describe Systematic Sampling.
How do you go about doing it?
Every nth person is selected from your target population.
A sampling frame is produced which has the names of the population in some kind of order e.g. alphabetical. The researcher then works through the sampling frame (or uses a computer) and collects every nth name until the sample is complete.
Describe Stratified Sampling.
How do you go about doing it?
Identify subgroups (e.g. age group) in the target population, then take a selection of participants from each subgroup but in proportion (using a random sample).
What are the strengths and weaknesses of Opportunity Sampling?
Strengths:
- a sample can be acquired quickly and takes less time
- a sample can be acquired inexpensively
Weaknesses:
- the participants might be nothing like a representative sample because not everyone in the target population will be at the place you choose.
- the sample may suffer from researcher bias as the researcher chooses participants
What are the strengths and weaknesses of Volunteer Sampling?
Strengths:
- the participants should have given their informed consent so it is ethically sound
- participants may be less likely to withdraw from the study as they chose to apply
Weaknesses:
- maybe biased an unrepresentative of the target population (volunteer bias + they may be different from non-volunteers)
- may be difficult to obtain large numbers of participants
What are the strengths and weaknesses of Random Sampling?
Strengths:
- avoids researcher bias as every member of the target population has an equal chance of being selected
- very representative sampling method
Weaknesses:
- almost impossible to carry out effectively unless the target population is small
- may by chance obtain an unrepresentative sample
- may end up with a biased sample as not all participants may want to take part
What are the strengths and weaknesses for Systematic Sampling?
Strengths:
- avoids researcher bias. Once the system has been decided the researcher has no say over who is chosen
- fairly representative sampling method
Weaknesses:
- made by chance obtain an unrepresentative sample
- may end up with a biased sample as not all participants may want to take part
What are the strengths and weaknesses of Stratified Sampling?
Strengths:
- most representative method because there is an equal representation of subgroups and participants are then randomly selected from these groups
Weaknesses:
- not all subgroups will have been sampled in this way so still not fully representative
- may end up with a biased sample as not all participants may want to take part
