Sampling Techniques Flashcards
What is random sampling?
A sample in which all members of the target population have an equal chance of being selected to participate in the research
What is a strength of random sampling?
As the researcher has no control over who is selected, investigator bias is avoided
What is a limitation of random sampling?
Although based on sound laws of mathematical probability that predicts that by chance samples should be representative, there is still a possibility they will not be, thus limiting generalizability
What is systematic sampling?
A mathematical selection of participants when the population size is divided by the sample size to dictate which participants are selected for the sample - every nth name from the sampling frame
What is a strength of systematic sampling?
The only input the researcher has is deciding the sample size, therefore it avoids investigator bias
What is a limitation of systematic sampling?
As with a random sample, there is still the possibility that the sample will not be representative thus limiting generalisability
What is stratified sampling?
This sampling method aims to ensure that the key characteristics of the population are represented in the same proportion in the sample
What is a strength of stratified sampling?
By guaranteeing that all key characteristics are present in the sample, it not only avoids investigator bias but is representative so can be generalised
What is a limitation of stratified sampling?
If all the key features of the population are not identified then the sample may not be representative
What is opportunity sampling?
A sample that consists of participants who were selected because of their availability
What is a strength of opportunity sampling?
Since the selection of participants is very straightforward it is less time consuming than other techniques
What is a limitation of opportunity sampling?
The researcher may consciously or subconsciously show bias in sample selection thus limiting generalizability
What is volunteer sampling?
A sample where the participants self-select
What is a strength of volunteer sampling?
Since the selection of participants is very straightforward it is less time consuming than other techniques
What is a limitation of volunteer sampling?
Sample bias is likely as only certain types of people are motivated to volunteer for research thus limiting generalisability
