Paper 3 Sampling Methods - HL Psychology

Convenience Sampling

Refers to gathering participants who happen to be available at the time of the study. This is a quick and easy way to obtain participants. However, sample may not be representative as participants might not have the characteristics of the target population.

May not represent the population

Random Sampling

A random sample is when every member of the target population has an equal chance of being asked to participate in the study. This should result in a very representative sample, thus, sample can be generalized to entire target population. However, it is a time consuming and expensive method, and often not feasible to carry out.

represent the population

Self-selected/ volunteer sampling

Participants are the ones that approach the researchers as volunteers to participate in the study, usually in response to some form of marketing or advertising from the researchers. Easy way to obtain participants. Participants freely chosen to participate, meaning they will usually be motivated and co-operative.

Advertise in areas where participants are likely to be

Snowball sampling

It is a sample that gradually increases in size after a small number of seeds originally selected ask more people to participate. Easy way to obtain participants, especially in studies that involve hard-to-reach populations. However, participants will come from the same social circle, meaning the sample may not represent the entire target population.

Not representative due to participant characteristicsthat may skew the data

Purposive Sampling

A sample that has been gathered because they have a particular set of characteristics that make them suitable for the study.

Advertise/recruit in areas where people with the salient characteristic will be

Stratified Sampling

Organised into relevant strata, drawn to represent the proportions within the population

Represent the population