SAMPLING Flashcards
What is a ‘population’
A group of people who are the focus of the researchers interest, from which a smaller sample is drawn
What is a ‘sample’?
A group of people who take part in a research investigation. The sample is drawn from the (target) population and is presumed to be representative of that population
What are ‘sampling techniques’?
The method used to select people from the population
What are the sampling techniques?
Random, systematic, stratified, opportunity and volunteer
What is random sampling and how is it done?
Every member of the target population has an equal chance of being selected
- TO DO - obtain a complete list of all the people in the target population and a sample is then selected from the full list in a random way;
- if its large the full list should be put into a computer and a random generator could select your sample
- If its a smaller sample, the full list of individual names could be put into a hat and pulled out until you have fulfilled your sample
What is the strength of random sampling?
There is no bias in the way the participants are selected, therefore the sample is likely to be representative of the target population
What are the limitations of random sampling?
- It can be very time consuming and often impossible to carry out
- Can still get an unrepresentative sample
- People may not be available on the day or simply don’t want to take part
What is systematic sampling?
When every nth member of the target population is selected
TO DO; a sampling frame is produced, which is n organised list of people in the target population. Then a sampling system is nominated/randomly determined and the researcher then works through the sampling frame until the sampling is complete
What are the strengths of systematic sampling?
- It avoids bias, as the researcher has no control over who is selected
- They will normally get a representative sample
- It is a fairly simple procedure
What are the limitations of systematic sampling?
- There’s a chance of a ‘freak’ sample
- It’s not as objective as random sampling (because the researcher may decide on how the people are listed before selection and on what number to use for ‘selection’
What is opportunity sampling and how is it done?
Selecting a sample from whoever is willing and available at the time of selection
TO DO; The researcher simply takes the chance to ask whoever is around at the time of their study
What are the strengths of opportunity sampling?
- Tends to be more ethical because the researcher can judge if the participant is likely too be upset by the study or is too busy to take part
- The researcher has more control over who is asked, meaning finding participants could be quick and easy and cost less
What are the limitations of opportunity sampling?
-There’s more chance of bias if the researcher may have more control over who is chosen and choose certain people leading to a biased sampl
What is volunteer sampling and how is it done?
Involves participants selecting themselves to be part of the sample
A researcher may place an advert in a newspaper or common notice board
What are the strengths of volunteer sampling?
It is easy, and requires minimal input and therefore less-time overall
