Sampling methods

Involves the researcher identifying members of the target population, numbering them and then attempting to draw out the required number of people for thier study. E.g. picking numbers out of a hat or having a computor generate participants.

+ more unbiased

-likely to be more representative of a target population

-time consuming

-possible to end up with a unbalanced, bias sample

Ask those who are around you, most easily available that represent the target population, to participate in the study.

+ convenient, quick, easy, and cheap

-higher chance of being bias

-researcher can influence those selected (process is not randomised)

Involves selection of every "nth" member of a target population. E.g. every 5th person on a list

+ unbiased

-chance of being biased

-bigger sample size. E.g. researcher requires 100 participants and picks them every 10th participant, would require 1000 participants

Sub-groups within the population are identified (e.g. boys and girls or age group) and then participants are gathered from each strata in proportion to their occurrence in the population.

+ representative of target population. Higher reliability and validity to make generalisation

-extremely time consuming

-people have to say yes to participate in research

Volunteers can be gathered in a number of ways e.g. putting out an advert to gather people to take part. This is a self selected sample

+ easy and relatively cheap

-can request specific characteristics/attributes +fast and efficient

-all of the participants are likely to be similar (specific type of person that responds to an advert)