AP Statistics

A statistical study of the entire group of individuals we want information about

Collects data from every individual in the population

A set of individuals in the population from which we collect data

A study that collects data from a sample to learn about the population from which sample was selected

Selects individuals from the population that are easy to reach

The design of a statistical study

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

Involves using a chance to process to determine are included in the sample

An individual from a population can be selected only once

An individual from a population can be selected more than once

Of size N is chosen in such a way that every group of N individuals in the population has an equal chance to be selected

Groups of individuals in a population who share characteristics thought to be associated with the variables being measured

Selects a sample by choosing an SRS from each stratum and combining the SRS’s into one overall sample

A group of individuals in the population that are located near eachother

Selects a sample by randomly choosing clusters and including each member of the selected cluster

Selects a sample from an ordered arrangement of the population by randomly selecting one of the first individuals and choosing every individual thereafter.

Occurs when some members of the population are less likely to be chosen or cannot be chosen in a simple

Occurs when an individual chosen for the sample can’t be connected or refuses to participate

Occurs when a systemic pattern of inaccurate answers to a survey question

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

Measures an outcome of a study

May help explain or predict changes in response variable

An experiment deliberately imposes treatments (conditions) on individuals to measure their responses

A treatment that has no active ingredient, but is otherwise like other treatment

A specific condition applied to the individuals in any experiment

The object to which a treatment is randomly assigned

When the experiment units are human beings

In an experiment, a factor is an explanatory variable that is manipulated and may cause a change in the response variable. The different are called levels.

Used to provide a baseline for comparing the effects of other treatments.

Describes the fact that some subject in an experiment will respond favorably to any treatment even an inactive

Neither the subjects nor those who interact with them and measure the response variable know which treatment a subject is receiving

Either subjects or the people who interact with them and measure the response variable don’t know which treatment a subject is receiving

A random assignment means that the experimental units are assigned to treatments using a chance process

Means keeping other variables constant for all experimental wins

Giving enough treatment to enough experiment units

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

The experimental units are assigned to the treatments completely at random

A group of experimental units that are known before the experiment to be similar in some way that is expected to affect the response to the treatments.

Random assignment of experimental units to treatments is carried out separately within each week

A common experimental design for comparing two treatments that use block for size 2

Examine existing data for a sample of individuals

Observational studies that track individuals into the future

The fact that different random samples of the same size from the same population produce different estimates

Observed results of a study are too unusual to be explained by chance

Individuals allow inference about the population from which the individuals were chosen

Individuals to groups allows inference about cause and effect