Sampling Flashcards
What is sampling?
Ideally, the sample that is drawn will be representative of the target population so that generalisation of findings becomes possible.
However, this can be difficult to achieve due to the diverse nature of individuals within a sample and therefore is likely to contain some degree of bias.
What are sampling techniques?
Samples are selected using sampling techniques that aim to produce a representative sample.
What is a random sample?
All participants have an equal chance of being selected.
Random sampling method
Number each person in target population.
Use random number generator to select 20 numbers at random.
OR
All names from target population are put into a hat.
Pull out 20 names.
Strengths of random sampling
It is free from researcher bias as they have no influence over who is selected.
Limitations of random sampling
Time-consuming and difficult to conduct.
No guarantee that it will be representative.
What is opportunity sampling?
Those people who are available at the time and willing to take part.
Strengths of opportunity sampling
It is a quick and easy way of choosing participants and it is convenient.
Limitations of opportunity sampling
Researcher bias - could approach people who look helpful.
Unrepresentative of the target population.
What is volunteer sampling?
Participants put themselves forward to be a part of a sample (self-selecting).
Volunteer sampling methods
Email target population asking for volunteers and select first ten responders.
Posters in the area with the target population, including the contact information. Select the first ten to get in touch.
Strengths of volunteer sampling
It is easy and requires minimal input, so it is less effort and time-consuming for the researcher.
It could produce more committed individuals which could be good if the task is boring/long.
No experimenter bias.
Limitations of volunteer sampling.
Volunteer bias - may produce a certain type of person and so may be unrepresentative of the population.
What is systematic sampling?
Every nth member of the target population is selected to take part.
Strengths of systematic sampling
Avoids researcher bias as once the system has been established the researcher has no influence over who is chosen.
