Survey and sampling. Flashcards
What are the two types of sampling methods?
Probability sampling involves random selection, allowing you to make statistical inferences about the whole group.
Non-probability sampling involves non-random selection based on convenience or other criteria, allowing you to easily collect initial data.
What are the Four main types of probability sampling methods?
Why would we want to use none probability sampling methods?
Non-probability sampling techniques are often appropriate for exploratory and qualitative research. In these types of research, the aim is not to test a hypothesis about a broad population, but to develop an initial understanding of a small or under-researched population.
What are the four methods of non probability sampling methods?
A convenience sample simply includes the individuals who happen to be most accessible to the researcher.
Voluntary reponse sampling: Instead of the researcher choosing participants and directly contacting them, people volunteer themselves
Purposive sampling This type of sampling involves the researcher using their judgement to select a sample that is most useful to the purposes of the research.
Snowball sampling: The number of people you have access to “snowballs” as you get in contact with more people.
What are the avantage and disavantage of simple random sampling without replacement (SRSWOR)?
Avantages:
1) Lack of Bias
2) Simplicity
Disadvantages
1) Difficulty Accessing lists of the full population
2) Time consuming: when the full list of a larger population is not always available.
3) Cost: if it time consuming it also money consuming.
What are the advantages and disavantages of stratified random sampling?
Avantages:
1) protect agaisnt selecting a bad sample
2) Smaller error in estimation and greater precision than the simple random sampling method.
Disavantages:
1) Must have prior knowledge of the population to be used.
2) overlapping could be an issue if there are subject that fall into multiple subgroups.
3) Like SRSWOR, having the full list of the population could prove challenging.
What are the avantage and disavantage of Systematic sampling?
Avantages:
1) simple
2) Sample will be evenly distributed
Disavantages:
1) The process of selection can interact with a hidden periodic trait within the population.
What are the avantages and disavantages of cluster sampling?
Avantages:
1) Cheap and quick.
Disavantages:
1) Of all the 4 random technic, cluster sampling is the least representative of the population. In other word the possibility of bias in the sample is high.
