Selection of participants Flashcards
In any study the group of individuals a researcher is interested in is called what?
The target population
The researcher wants to do what about the target population?
The researcher wants to make a statement about the target population
What is a sampling frame?
The researcher obviously cannot study all the people in the target population so instead the researcher starts by identifying a smaller group so draws a sample that will be representative of the target population
Why does the researcher used a sample?
So that generalisations can be made about the target population
In order to select a representative example psychologists have a range of sampling techniques, what are they?
Opportunity sample volunteer sample, random sample, systematic sample snowball sample sratified sample quota sample
What is an opportunity sample?
Selecting people who are most easily available at the time of the study
What is a volunteer sample?
Produced by asking for volunteers - The volunteers select themselves
What is a random sample?
Every member of the target population has an equal chance of being selected
What is a Systematic sample?
Selecting every nth person for example every fifth or 10th
What is a snowball sample?
Relies on referrals from initial participants to generate additional participants
What is a stratified sample?
Participants are selected according to their frequency in the population
What is a quota sample
It is the same as a stratified example that is participants are selected according to their frequency in the population
What are the advantages opportunity sample?
It is the easiest method because you just use the first participant you can find which means it’s quicker than other methods
What are the disadvantages of the opportunity sample
It is inevitably biased because the sample is drawn from a part of the target population. For example asking people in the street on a Monday morning is like to exclude professional people because they were at work
What are the disadvantages of the sample opportunity
Sample is biased because participants are likely to be keener and therefore more helpful most would-be or just more inquisitive this results in a volunteer bias
What are the advantages of a random sample
This is potentially biased because all members of the target population have an equal chance of selection
What are the disadvantages of a random sample
This form of sampling takes more time and effort than other methods because you need to obtain a list of all the members of your target population
The advantages of a systematic sample
Unbiased as participants are selected using an objective system
What are the disadvantages of a systematic sample
Not truly unbiased/ random unless you select a number using a random method start with this person and select every person
What are the advantages of snowball sampling?
Enables a researcher to locate groups of people who are difficult to access
What are the disadvantages of snowball sampling
The sample is not likely to be a good cross-section from the population because it is friends of friends
What is the advantage of a stratified full quota sample?
Likely to be more representative than other sampling techniques because there is equal representation of subgroups
What is the disadvantage of stratified or quota sample
Although the sample represents subgroups each project may be biased in other ways
