AP Statistics Vocabulary

biasedany systematic failure of a sampling method to represent its population
stratawhen groups of experimental units are similar, they are gathered into these groups
censusa sample that consists of the entire population
clustersampling design in which entire groups are chosen at random
completely randomizedtype of experiment in which all experimental units have an equal chance of receiving any treatment
confoundingwhen the levels of one factor are associated with the levels of another factor so their effects cannot be separated
controlaspects of the experiment that we know may have an effect on the response, but that are not the factors being studied
control groupexperimental units assigned to a baseline treatment level
conveniencesampling design where individuals are chosen based on who is easily available
double blindneither the subjects nor the people who have contact with them know which treatment a subject has received
experimental unitsindividuals on which an experiment is done
experimentsstudy in which subjects are randomly assigned to treatments
factorvariable whose levels are controlled by the experimenter
heterogeneousnot similar in makeup
homogeneoussimilar in makeup
levelspecific values that the experimenter chooses a factor
matched pairstype of study in which subjects who are similar in ways not under study may be grouped together and then compared with each other on the variables of interest
multistagesampling schemes that combine several sampling methods
nonresponsetype of bias that is problematic because the intended sample is incomplete
observational studystudy based on data in which no treatments have been assigned to subjects
outcomean individual result of a component of a simulation
placebotreatment known to have no effect, administered so that all groups experience the same conditions
placebo effectthe tendency of many human subjects to show a response even when administered a fake treatment
populationthe entire group of individuals or instances about whom we hope to learn
prospectiveobservational study in which subjects are followed to observe future outcomes
random behavioran occurrence for which we know what outcomes could happen, but not which particular values will happen
randomizationprocess by which each individual is given a fair chance of selection
responsetype of bias that is problematic because false information may be given
retrospectiveobservational study in which subjects are selected and then their previous conditions or behaviors are determined
samplea (representative) subset of a population, examined in hope of learning about a population
simple randomsampling design in which each set of n elements in the population has an equal chance of selection
sampling framea list of individuals from whom the sample is drawn
sampling variabilitythe natural tendency of randomly drawn samples to differ, one from another
sample surveya study that asks questions of a sample drawn from some population in the hope of learning something about the entire population
simulationmodels random events by using random numbers to specify outcomes with relative frequencies that correspond to the true real-world relative frequencies we are trying to model
single blindwhen either the subjects or the people who have contact with them do not know which treatment a subject has received
statistically significantwhen an observed difference is too large to believe that it is likely to have occurred naturally
blocka subdivision of the population
stratifiedsampling design in which the population is divided into several strata, and random samples are then drawn from each stratum
subjectspeople who are studied
systematicsample drawn by select an individual from a list and then each of the next N individuals from the sampling frame
treatmentthe process or intervention applied to randomly assigned experimental units
trialthe sequence of several components representing events that we are pretending will take place
undercoveragetype of bias that is problematic because some groups are not represented in the sample
voluntary responsetype of bias that is problematic because those who volunteer tend to have strong negative opinions
voluntary responsesampling design where individuals can choose on their own whether to participate in the sample
wording biasa type of response bias where the question is posed to achieve a desired result