Sampling Flashcards
Why is a sample being too small an issue?
it may not be representative
it may not be reliable
data is hard to generalise
why is a sample being too big an issue?
it may be too expensive
it could take too long
what is random sampling?
where everyone in the research population has an equal chance of being selected
advantages of random sampling
can help to reduce biases
a large enough sample should reflect the characteristics of the whole research poplation
disadvantages of random sampling
may take a long time as you need to have a list of all members of the research population and then contact them
may not be fully representative of target population if sample is too small
what is systematic sampling?
listing all of your potential participants and selecting every nth person
advantages of systematic sampling
unbiased as participants are selected using an objective system
creates a representative sample
disadvantages of systematic sampling
method is not truly unbiased unless you select a random number using a random number using a random method and start with this person, and then select every nth person
What is stratified sampling?
dividing the sampling frame into smaller groups then randomly selecting proportional amounts of people from each group
advantages of stratified sampling
likely to be more representative than other methods
disadvantages of stratified sampling
very time consuming to identify sub-groups
complete representation of the target population is not possible
what is quota sampling?
dividing the sampling frame into a number of smaller groups (such as, age, gender, ethnicity) and taking a set number from each group
once you have reached your quota, then you stop collecting the sample in that area
advantages of quota sampling
represents specific subgroups
disadvantages of quota sampling?
can create bias as the selection process isnt random
what is snowball sampling?
researchers find a few participants and then they ask them to find participants themselves, and so on
