Sampling Techinques (research methods) Flashcards
What are the key terms
Target population- the wider group of people that research findings should apply to
Sample- the section of the target population which is chosen to take part
Biased sample- a sample that is not representative of the target population
Representative sample - a cross section that is typical of the target population
What are the different types of sampling ?
Opportunity Self selected Random Snowball Stratified
What is opportunity sampling?
Participants are chosen because they are convenient- those who are there at the time and willing to take part
What are the strengths of opportunity sample?
- less time consuming than other techniques because time is not spent planning and selecting. Convenient
- researcher can’t bias the selection. Because they just have to use who is there
What are the weaknesses of opportunity sample ?
Unrepresentative because-
- there may be an imbalance of gender/age/ ethnic group
- if people come from the same locality they may be similar in terms of their characteristics( eg all psychology students) or they may have similar attributes
What is self- selected sampling ?
Participants volunteer themselves to take part in the study, for example in response to a newspaper advertisement/ email
What are strengths of self- selected sampling
- the ppts i your sample are liking volunteers- more ethical
- may be more likely to focus on the task and the It seriously
- may get a wide range of ppts
What is random sampling ?
Every member of the target population has an equal chance of being selected e.g selected by a random number generator from the electoral roll
The target population is identified eg all y12 students in KES sixth form
A method is used to select a sample from all members
Eg all names out in a hat and 29 boys names and 20 girls names pulled out
What are the strengths of random sampling ?
- It avoids bias as the researcher has no control over who is selected
- The researcher will normally get a representative sample
What are weaknesses of random sampling ?
- it is time consuming because all potential participants need to be identified before a sample can be drawn.
- there is a small chance that a ‘freak’ sample may be drawn, which would be unrepresentative eg 20 females 5 males
What is snowball sampling ?
Pick one person from the target population to take part and ask them to tell a friend to come and take part and so on
What are the strengths of a snowball sampling
Useful when the ppts you need are not easy to find eg a study on students taking illegal substances
What are the weaknesses of snowball sampling ?
Can be highly unrepresentative
What is stratified sampling ?
Mirroring proportions of the whole situation
What are strengths of stratified sampling ?
Should be representative of the target population