AP Stats Chpt 4 Vocab

does not attempt to influence response

imposes some treatment on individuals

entire group of individuals

part of the population we actually examine

asking a part of a population

attempts to contact every individual

people choose themselves to respond

choosing individuals who are easy to reach

every individual has an equal chance of being chosen. Also, every “group” has an equal chance of being chosen

divide population into groups(strata); do an SRS within each group

population is already divided into groups (clusters)

when you favor one outcome

some groups of the population are left out of the process of choosing the sample

an individual chosen cannot be contacted or does not cooperate

behavior of the respondent or interviewer changes the answer

drawing conclusions

individuals in an experiment

humans (if units are humans, they are called subjects)

explanatory variable(s)—can be more than one

specific experimental condition (list out every possibility)

what you are measuring

dummy treatment

group who received no or placebo treatment

neither subjects nor those who measure the response variable know which treatment a subject recieved

the effects of lurking variables on the response (compare 2 or more treatments)

each treatment on many units to reduce chance of variation in the results

use impersonal chance to assign experimental units to treatments

all units are assigned a treatment at random

group of units that are known to be similar before the treatments

block 2 units together based on similar traits

cannot realistically duplicate conditions we want to study

an observed effect so large that it would rarely occur by chance