Simple Random Samples (SRS)
An SRS of size n individuals from the population are chosen in a way that every set of n individuals has an equal chance to be in the sample actually selected.
stratified random sample
divide the entire population into 2+ strata that share 1+ characteristics. Random sampling (often SRS) to draw individuals from each stratum. Combine individuals selected from each stream to form overall sample. (used when results to be similar within strata but diff. within members of diff. strata)
cluster sample
group entire population into clusters, then randomly select a sample of clusters. Sample all individuals in clusters
Systematic sample
randomly choose 1st individual for sample, individuals chosen at set interval from then
convenience sample
any sampling method that systematically leaves out large groups due to convenience
voluntary response sample
any survey in which authors of survey have no control of who responds