Sampling Techniques Flashcards
What is the definition of sampling unit?
One member of a sample or survey population
What is the definition of sampling frame?
A list of members of the survey population
What is the definition of survey population?
The group of people you are interested in studying
What is random sampling? What is good and bad about it?
People are picked at random from a list of names.
- Everyone has an equal chance of being picked
- BUT relies on chance that the sample is representative
What is systematic random sampling? Whats bad about it?
Names are selected from a sampling frame at regular intervals.
- Relies on chance to be representative
What is stratified random sampling? What is good and bad about it?
Sample tries to reflect the characteristics of the survey population
- Most representative random sample technique
- May not be possible to find the stratifying information you want from the sampling frame
What is quota sampling? What is bad about it?
Interviewers find people to fit pre-set quotas
- Not everyone has an equal chance of being chosen
- Need to know the proportions of the different groups in the population to set the initial quotas
What is multi-stage sampling? Whats bad about it?
A sample is selected in stages
- If the first sample is not representative, then subsequent samples may be inaccurate
What is snowball sampling? Whats bad about it?
Used if its difficult to find people for a sample. Researcher finds on suitable person, asks for an introduction to others which leads to a chain of introduction and a sample is produced.
- May only get a particular type of respondent
What is volunteer sampling? Whats bad about it?
The research is advertised and volunteers sign up.
- Difficult to ensure the sample is representative
What is a non-representative sample?
A group is selected for a particular purpose, which is not representative because it has the particular characteristics you want to study.
