Sampling Flashcards
What is Stratified Sampling?
Advantages/Disadvantages?
The population is split into sub-groups called strata, the sample size of the strata is then proportional to the size of the population.
Advantage=Very representative of each strata and therefore the population
Disadvantage= As it requires greater precision it often requires greater expenses
What is Cluster Sampling?
Advantages/Disadvantages?
Cluster Sampling takes several clusters that should be reasonably representative of the entire population and then samples these clusters.
Advantage= Cheap, quick and easy Disadvantage= Not as precise as simple or stratified as high chance clusters aren't representative of whole population
What is Systematic Sampling?
Advantages/Disadvantages?
Systematic sampling chooses people based on going up in a certain order (ie start at 10 and select every 60th person from there) AVOID CYCLIC PATTERNS
Advantage= Easy, cheap and quick Disadvantage= Not all samples are possible so possibly not representative
What is Quota Sampling?
Advantages/Disadvantages?
An interviewer chooses who to sample and tries to choose people who would be representative of the population
Advantage= Very cheap Disadvantage= Definitely not random
What is Simple Random Sampling?
Advantages/Disadvantages?
In simple random sampling every possible sample of a given size is equally likely to be chosen, because every member of the parent population is equally likely to be chosen.
Advantage= Representative and random Disadvantage= Time consuming and potentially expensive
What are the requirements of a sample?
What’s the advantage of a sample being random?
Unbiased and representative of population
allows proper statistical inference to be undertaken, because we know the probability basis on which it has been selected
