AP Stat Unit 4

observe individuals and collect data without any interference with conditions

retrospective and prospective

an observational study that has already occured

an observational study being studied as it ocurs

deliberately impose some treatment on individuals to observe their responses

things that get in the way

mimic a situation and is alternative method for producing data when it may not be possible to carry out the experiment

the entire group from which you want to collect data

part of the population that is actually examined

involves studying a part in order to obtain information about the whole group

when every member of the population is accounted for

measure the outcome of the study

acounts for predicts and explains changes in the response variable

every possible set of n size individuals has an equal chance of being selected

1st divide population into groups then perform SRS on each strata

strata

1st person is selected then each nth member after that

divide the population into groups, randomly select a group and survey all members of that group

sample based on avaliability

confounding variables, under-coverage, non response, voluntary response, and response bias

when an entire group is excluded and not represented and did not have the opportunity to be included

when someone is chosen to participate and chooses not to

people who chose to participate

respondents lie within answers

an entire population

a specific sample

the list of individuals from which a sample is actually selected

control: by comparing different treatment you can control outside influences

randomization: makes more impersonal which decreases bias

replication: repetition of experiments decreases variation

relates to a design of an experiment (randomize within each block) reduces variation!

what or who you are performing the experimentation people are usually known as subjects

are explanatory variable

when different values of an explanatory variable are used

condition being applied to the experimental unit (#factors)(#levels)=#of treatments