CHP. 7 - Sampling Flashcards
Census
All collecting data from all units in a population
Sample
Selection of a subset of a population
Probability Sampling
Representative sample
- all members of the population have equal chance of being included in the sample
Nonprobability Sampling
Biased sample
- a subpopulation is systematically excluded in a sample compared to general population
Convenience Sampling
Sampling only those that are easy to contact
- ex. polled just a classroom as a teacher
Self-Selection (Volunteer) Sampling
Responses are only those who care enough about the topic to respond
- ex. online pools, product ratings
Simple Random Sampling
Each member of population has an equal chance of being selected
- can be difficult & time-consuming
Cluster Sampling
Clusters of populations are randomly selected & then all individuals in the cluster are used
Multistage Random Sampling
First, randomly select from clusters
Second, randomly select individuals within each chosen cluster
Stratified Random Sampling
Select particular demographics/categories then randomly sample within each category
Oversampling
Selection over-represents 1+ groups
- variation of stratified
Systematic Sampling
Random sample with a fixed periodic interval is selected from a larger population
Purposive Sampling
Researchers recruit a particular subgroup of the population in a non-random way
- biased
Snowball Sampling
Participants are asked to recommend others for the study
Quota Sampling
Researchers identify subset of population of interest & set quota
- quota filled non-randomly
- equal number of subjects in each group but not representative
- biased version of stratified
