Data Flashcards
Population
The whole set of items that are of interest
Census
Observes / measures every member of the population
Sample
A selection of observations taken form a subset of the population, used to find information about the population as a whole
Sampling unit
Individual units of a population
Sampling frame
The named / numbered list of sampling units
Random sampling
Each member of the population has an equal chance of being selected, every possible subset has an equal chance of being selected.
Population must be finite to fo this.
Non-random sampling
Each member / subset does not have an equal chance of being selected.
Used for infinite populations.
Finite population
Where you know and can count all the members
Infinite population
Where it is not possible to count all the members
Which sampling methods can only be used for finite populations?
- Simple random sampling
- Stratified sampling
- Systematic sampling
Which methods of sampling can be used for both finite and infinite populations?
- Opportunity sampling
- Quota sampling
- Cluster sampling
Simple random sampling
Produces a truly ra
Stratified sampling
Divides population into strata, and takes a sample from each proportional to the size of the strata in the population.
Systematic sampling
Elements are chosen at regular intervals with the first element chosen randomly.
Opertunity sampling
Taking sample from the members of a population available until the desired sample size is reached
Quota sampling
A set numbers of members of each subset are sampled with the number of members selected being proportional to the size of subset in population.
Cluster sampling
Population is split onto smaller groups (clusters), clusters are then chosen at random and members selected from these groups
