Stat sampling definitions

Parameter

numerical characteristic or proportion of population of interest

Statistic

numerical characteristic or proportion of sample

Simple random sample

Every unit or individual in a population has an equal chance of being selected (randomly generated)

Stratified random sample

divide population into sub-population (strata) of similar units and use SRS to select from each stratum

Cluster sampling

population divided into clusters, select a sample of clusters

Sequential or skip sampling

sample every x observation

voluntary response sampling

sample consists of those who volunteer to participate

convenience sampling

selects individuals who are readily available

voluntary response bias

sample is only of people who self select to participate

non-response bias

people who decline to respond may be different than those who do respond

response bias

sometimes incentive to lie; maintain self image, avoid confrontation, framing of question

sampling frame

complete and accurate list of all individuals in the target population