AP Stats Unit 3 Vocabulary

the entire group of individuals about which we want information about

a subset of the population from which data are collected

choosing individuals who are easiest to reach

people choose to be in the sample by responding to a general invitation

a design that is very likely to underestimate or overestimate the value you are measuring

an individual from a population can be selected only once

a selected individual is placed back into the population and could be chosen a second time

a sample of size n selected from the population in such a way that each possible sample of size n has an equal chance of being selected.

selects a sample by choosing a SRS from strata, groups that share something in common, and combining to make a sample.

selects a sample by randomly choosing clusters, groups representative of the population, and including each member in the cluster

randomly select an arbitrary starting point and then select every kth member of the population

collects data from every individual in the population

occurs when some members of the population are less likely to be chosen in a sample

occurs when an individual chosen for the sample can't be contacted or refuses to participate

occurs when there is a consistent pattern of inaccurate responses to a survey question

observes individuals and measures variables of interest but does not attempt to influence the responses

deliberately imposes some treatment on individuals to measure their responses

measures an outcome of a study

may help explain or predict changes in a response variable

occurs when two variables are associated in such a way that their effects on a response variable cannot be distinguished from each other

a specific condition applied to the individuals in an experiment

an explanatory variable that is manipulated and may cause a change in the response variable

the experimental units are assigned to the treatments completely by chance

the random assignment of experimental units to treatments is carried out separately within each block

A method of assigning subjects to groups in which pairs of subjects are first matched on some characteristic and then individually assigned randomly to groups.

an experiment needs to compare at least two groups

use random change to assign experimental units to treatments

keep other variables that might affect the response the same for all groups

each treatment group has sufficiently enough experimental units