unit 4 ap stats vocab

census

collects data from every indivudual in a population

convience sample

choose people who are the easiest to reach

volunatry response sample

open to invitation to respond

simple random sample

gives every possible sample of a given population the same chance to be chosen

stratified random sample

divide the population into groups of indivudals that are similar in some way

strata

groups of unique indviudals

cluster sample

groups of population that are located near eachother. called a cluster and then randomly select a cluster to sample.

systematic random sample

select a value of population. then choose a random indivuidual then choose a radom number and choose every indiuvdal on that number

undercoverage

less likely to be chosen or cant be chosen

non response

can not be contacted or refuse to answer.

response bias

untruthful answers or poorly worded questions

explantory variable

the trial

response variable

the response to the trial

confounded

when an outside force could be changing the response not the explantory

observational studies

no treatment is provided and srs

experiments

a treatment is provided and population is chosen with a srs

factors

the treatments given to the subjects

double blind

neither the patient or doctor knows what treatment is being given

single binding

the doctor knows what experiment is being given

control

no treatments given to see the effects of the treatments on others

replication

each treatment is given to mutiple subjects

block design

forms groups in an experiment . then given treatments at random to the block

matched pairs design

2 similar subjects paired together one is given one treatment the other is given the other

sampling varaiblity

differnent random samples of the same size and population can producediffernt estimates