stats sampling & bias definitions

census

collected data from all individuals in a population

SRS

a sample where every individual in a population has an equal chance of being chosen

stratified random sample

a sample where the main population is separated into groups based on their strata(similar characteristics) 

cluster random sample

a sample where the main population is separated into smaller populations that are supposed to represent the full population

systematic random sample

a sample where data is collected by randomly choosing a starting point and then sampling at a fixed periodic interval

undercoverage bias

when some groups in the population are less likely to be chosen

nonresponse bias

when individuals picked to be in a sample don’t respond back/refuse to comply

response bias

when participants in a study to give inaccurate or misleading answers to questions

voluntary response

when an invitation is sent out to all individuals in a population, but only those who choose to respond reply

convenience sampling

a sample where participants are chosen based on their easy accessibility and willingness to participate, rather than through random selection