Sampling techniques Flashcards
What are sampling techniques?
Sampling techniques refer to how participants are recruited
What is the population?
The population is a group of people who are the focus of the researcher’s interest, from which a smaller sample is drawn
What is the target population?
The target population is a subset of the general population
What is a sample?
A group of people who take part in research investigation. The sample is drawn from a target population and is presumed to be representative of that population
How many sampling techniques are there?
There are five sampling techniques:
- Random sampling
- Systematic sampling
- Stratified sampling
- Opportunity sampling
- Volunteer sampling/ Self selected samples
What is random sampling?
A random sample is a form of sampling in which all members of the target population have an equal chance pf being selected
What is a strength of the sampling technique - random sampling? (researcher bias)
A random sample is free from researcher bias. the researcher has no influence over who is selected and this prevent them from choosing people who they think may support their hypothesis
What is a limitation of the sampling technique - random sampling? (time + difficulty)
Random sampling is difficult and time consuming to conduct. A complete list of the target population of the target population may be extremely difficult to obtain. Furthermore you may end up with a sample that is still unrepresentative.
What is systematic sampling?
A systematic sample is when every nth member of the target population is selected.
What is a sampling frame?
A sampling frame is a list of people in the target population organised into groups, for example alphabetical order
What is a strength of the sampling technique - systematic sample? (researcher bias)
This sampling methods avoids researcher bias. Once the system for selection has been established the researcher has no influence over who is chosen
What is a limitation of the sampling technique - systematic sample? (time)
Systematic sampling can be time consuming to conduct.
What is a stratified sample?
A stratified sample is a sample selected so that specified groups will appear in numbers proportional to their size in the target population, within each subgroup (strata) participants are selected on a random basis
What is a strength of the sampling technique - stratified sample? (representation)
Stratified samples produce a representative sample because they are designed to accurately reflect the composition of the population. This means that generalisation of findings become possible
What is a limitation of the sampling technique - stratified sample? (available knowledge)
Stratification requires detailed knowledge of a population which may not be available and takes a long time to acquire such information.
What is opportunity sampling?
Opportunity sampling is when a sample is obtained when researchers decided to select anyone who happens to be willing and available
What is a strength of this sampling technique - opportunity sampling? (convenience, time and money)
Opportunity sampling is a convenient technique. This method save the researcher a good amount of time and effort. Additionally it is much less costly in terms of time and money compared to other sampling techniques, like random sampling
What is a limitation of this sampling technique - opportunity sampling? (two forms of bias)
Opportunity sample suffer from two forms of bias. Firstly sample tend to be unrepresentative of the target population as it is drawn from a very specific area, so findings cannot be generalised. Secondly, there can be researcher bias as the researcher has complete control over the selection of participants.
What is volunteer sampling?
Volunteer samples involve participants selecting themselves to be part of the sample, referred to self selection
What is a strength of this sampling technique - volunteer sampling? (effort + time)
Volunteer samples are one of the easier forms of sampling. It requires minimal input from the researcher and so is less time consuming than other forms of sampling
What is a limitation of this sampling technique - volunteer sampling? (volunteer bias)
Volunteer bias is created from volunteer sampling. Asking volunteers may attract a certain demographic/”profile”. As a results any findings may be harder to generalise to wider population.
