Research Methods - Populations, samples and sampling techniques Flashcards
What is a target population?
The section or group of people that the researcher wants to study e.g. autistic people in Baron-Cohen study
What is a sample?
A group of selected participants which relate to the target population of the study
What is a random sample?
When every member of the target population has an equal chance of being selected to be in the sample
What must you have to obtain a random sample?
A clear and finite target population with a full list of members to be drawn up
How does a snowball sample work?
Once one participant is studied, the researcher will ask the ppt if they know anyone who might be interested in taking part in the research
What is the disadvantage of a snowball sample
The sample can become very bias as they will be of the same age or from the same place
What is an opportunity sample?
Where the most convenient people are selected to participate in the study
What is a problem faced with opportunity samples?
The sample can become bias as researchers can choose their preferences of sample for the research - this would mean that the sample is not representative of the target population
What is a benefit of opportunity samples?
Gives researchers access to large numbers of easy-to-access participants
What is a self-selected sample?
Where ppts choose to take part in a study
How would you obtain a self-selected sample?
Advert in a newspaper or notice board
Sending out postal questionnaires
What problems could be faced with a self-selected sample?
The sample will only contain people who have seen the advert (so may be from the same place, read the same type of newspaper etc.) so there could be some extraneous variable affecting the sample
What is the benefit of a self-selected sample?
You can rely on them more to take part in a lengthy study as they signed up for it in the first place
