stratfied sample
A sampling method where you do a SRS from each homogeneous (similar) group created from the population.
cluster sample
A sampling method where you randomly choose entire (heterogeneous) groups created from the population.
population
An entire group of individuals about whom we hope to learn.
experiment
A study where treatments are randomly assigned to subjects.
sampling varability
The naturally occurring variability from one sample to another sample.
simple random sample
A sample in which every possible group of size n is equally likely to be chosen.
population perimeter
A value that measures a characteristic of a population.
bias
A systematic failure of a sample to represent its population that leads to either an over or an underestimate of the variable.