Sampling Methods: Target Populations & Samples | AQA GCSE Psychology Revision Notes 2019

Samples & target populations

A sample consists of the participants who will take part in the research
A sample is taken from the population that is relevant to the research topic. e.g.

A target population tends to have distinct characteristics which are of particular interest to the researcher
Once the target population has been identified the researcher draws a sample from that population
Often a sample is taken from a population which is more generalised (i.e. not so specific) than a highly specific target population, e.g.

Research which investigates the effect of loud music on concentration can draw its participants from a wide range of people
Research on the duration of STM does not require a highly specific sample (generally anyone from the age of 18-60 would suffice)

Remember that a sample is not the same thing as a population:

A population is composed of all the members of a particular group or sector of society (e.g. all teen mothers in the UK)
A sample is taken from that group or sector (e.g. teen mothers in the Greater London area).

Once the research process is over the researcher analyses their findings and draws conclusions based on these findings
One of the issues in using a small, limited or highly specific sample is that it is very difficult to generalise the findings beyond the scope of this sample, e.g.

A sample of 25 office workers from Glasgow in Scotland does not represent office workers in other parts of Scotland or the UK therefore the findings from such a sample can only apply to other office workers (within the same age range as those in the sample) from Glasgow
To make the sample more representative the researcher should use a cross-sectional sample e.g. office workers from other parts of the UK

The data from a small sample e.g. 25 office workers is not robust therefore the quantitative findings are less likely to stand up to analysis via statistical methods i.e. the researcher may find that the IV has not affected the DV (which a waste of their time and resources)
Larger samples are more robust and reliable data
There are several reasons as to why small samples may be used in psychological research:

Running research is expensive so it may only be possible to conduct a snapshot study with a small sample
It may be difficult to find enough participants to take part in the study, particularly if the research requires a very specific sample
The researcher does not have very much time in which to conduct the study so they use whichever participants are most convenient e.g. university students
Some types of qualitative research such as case studies and interviews tend to use very small samples but these are the exception; most research studies require large samples

Any sample which uses participants who, for example, are from the same town, are the same age, possess similar personality traits, is a biased sample i.e. the results are difficult to generalise

Here is an example of a question you might be asked on this topic - for AO1.

AO1: You need to demonstrate knowledge and understanding of key concepts, ideas, theories and research.

Question: Which one of the following statements about samples and populations is correct?

Select one answer only. [1]

Model answer: