Introduction to Experimental Design - AP Statistics

Bias introduced by the method of selecting participants. Non-representative sampling distorts results.

Single-blind conceals from subjects; double-blind from subjects and experimenters. Double-blind also conceals from experimenters.

Extent to which results can be generalized to other contexts. Measures generalizability beyond study conditions.

Observes a population at a single point in time. Snapshot of population at one moment.

A change in behavior due to awareness of being observed. Behavioral modification due to observation awareness.

To ensure representation across key subgroups. Maintains proportional representation across strata.

Dividing the population into groups and sampling entire groups. Samples natural groups rather than individuals.

Selecting every $k^{th}$ individual from a list. Regular interval selection from ordered list.

A variable that is not considered but affects the outcome. Hidden variable that may influence results.

All combinations of factors are tested. Tests all possible factor combinations systematically.

To provide a baseline for comparison. Essential reference point for measuring treatment effects.

Experiments involve manipulation; observational studies do not. Key distinction is researcher control of variables.

An individual or object to which a treatment is applied. The basic entity receiving experimental treatment.

A specific condition applied to experimental units. The experimental intervention being tested.

A group that receives no treatment or a standard treatment. Provides baseline comparison for treatment effects.

Random assignment of treatments to experimental units. Ensures unbiased treatment allocation.

Applying treatments to multiple experimental units. Increases reliability and statistical power.

An explanatory variable manipulated in the experiment. The independent variable controlled by researchers.

Both subjects and experimenters do not know the treatment assignments. Eliminates bias from both participants and researchers.

A change in response due to the belief in treatment efficacy. Psychological response to perceived treatment.

A design where units are paired, and each pair receives different treatments. Controls for individual differences effectively.

Reduces bias and balances confounding variables. Eliminates systematic differences between groups.

A variable that influences both the response and explanatory variables. Distorts true treatment effects through correlation.

When the effect of one factor depends on another factor. Factors combine to create different effects.

A specific value or category of a factor. Different settings or values of a factor.

Observes a population at a single point in time. Snapshot of population at one moment.

Extent to which results can be generalized to other contexts. Measures generalizability beyond study conditions.

The degree to which the study accurately reflects causal relationships. Measures accuracy of causal conclusions within study.

Bias introduced by the method of selecting participants. Non-representative sampling distorts results.