AP STATS types of experiments

Bias

The design of a statistical study systematically favors certain outcomes.

Block

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

Cluster Sample

All individuals in the chosen group are included in the sample.

Convenience sample

A sample selected by taking the members of the population that are easiest to reach

Double-blind

An experiment in which neither the subjects nor those who interact with them know which treatment a subject received.

Explanatory Variable

A variable that helps explain or influences changes in the other variable

Lurking variable

A variable that is not among the explanatory or response in a study but that may influence the response variable.

Matched pair

A common form of blocking for comparing just two treatments.

Observational study

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

Placebo effect

Describes the fact that some subjects respond favorably to any treatment, even an inactive one.

Randomized Block Design

Random assignment of treatments is carried out separately within each block.

Random sampling

A variable that measures an outcome of a study.

Response variable

A variable that measures an outcome of a study.

Simple random sample (SRS)

Gives every possible sample of a given size the same chance to be chosen.

Single-blind

An experiment in which either the subjects or those who interact with them, but not both, know which treatment a subject received.

Stratified random sample

First classify the the population into groups of similar groups of individuals then choose a separate SRS from each group to form the full sample