AP Statistics: Bias, Studies, and Experimental Design

A comprehensive vocabulary review set covering bias and sampling, types of studies and variables, and experimental design concepts for AP Statistics.

Bias

When results are unfairly influenced and don't accurately represent the population.

Selection bias

When the way people are chosen makes the sample unfair.

Undercoverage

When certain groups of people are left out of a sample.

Convenience sampling

Choosing people because they're easy to reach.

Measurement/response bias

When the way information is collected leads to inaccurate answers.

Nonresponse bias

When selected people don't respond, which can affect the results.

Observational study

Researchers watch or collect information without changing anything.

Experiment

Researchers change something to see what happens.

Confounding variable

Another factor that makes it hard to tell what caused the results.

Response variable

What you measure in an experiment (the outcome).

Explanatory variable

What you change or use to explain the outcome.

Experimental condition (treatment)

The specific treatment given to a group.

Experimental units

The people or things receiving the treatment.

Random assignment

Putting people into treatment groups by chance.

Replication

Using enough subjects or repeating treatments to make results more reliable.

Extraneous variable

An outside factor that might affect the results.

Direct control

Keeping outside factors the same for everyone.

Blocking

Grouping similar subjects together before comparing treatments.

Single-blind experiment

Subjects don't know which treatment they're getting.

Double-blind experiment

Neither subjects nor the people measuring results know who got which treatment.

Control group

A group used for comparison that doesn't receive the treatment being tested.

Placebo

A fake treatment with no active ingredient.