ap stats ★ unit 3 terms

the one no math unit I desperately need to know how to differentiate between :,,)

voluntary response

a way of sampling in which people choose to respond; those that choose to respond tend to have strong opinions

convenience sample

a high biased way of sampling which is of easy reach (hence the name). it often leads to overestimation.

simple random sample (SRS)

a low biased way of sampling where individuals are labeled and then randomized (via generator or shuffling). has less variability

stratified clustered random sample

splits the population into mixed group and randomly selects a group to sample everyone in (cluster)

stratified random sample

splits the population into like groups, and then performs SRS to choose something from each group

systemic random sampling

a method where the start point is chosen at random and then chooses equal intervals (ex: starts at 10th sample and picks one for every 3 samples)

undercoverage

occurs when some part of the population is excluded from the sample (ex: sample from landlines, missing younger people because older people only have landlines)

nonresponse bias

occurs when an individual is selected to response but chooses not to respond

response bias

occurs when there is a pattern of inaccurate results (ex: wording of the question, lying)

observational study

a study where no treatment is imposed and it results only show correlation

experiment

a study where the treatment is imposed/manipulated. results show causation

explanatory variable

a variable of the study that is independent, can be controlled

response variable

a variable of the study that is dependent, cannot be controlled, is the outcome

confounding variable

a variable that can also contribute to the outcome; is not explanatory

control group

a group that provides the baseline for comparison

blinding

a condition where the subjects don’t know what treatment is given to them

double blind

a condition where BOTH subjects and experimenters don’t know what treatment is given

randomized block design

groups experimental units into similar groups (ex: age is split into two, one age group splits into group a or group b while the other age group splits into group a or b aswell)

matched pairs

where subjects are paired and then randomly assignment to a treatment; subject received all treatments but the order of treatments are random