AP Stats Experimental Design

Question 1

What is the primary purpose of a control group in an experiment?

Accepted Answer

To provide a baseline for comparison against the treatment group

Answer

The control group serves as a reference point, allowing researchers to determine whether the treatment had an effect.

Question 2

What is random assignment and why is it important?

Accepted Answer

Randomly placing participants in groups to equalize confounding variables

Answer

Random assignment distributes known and unknown confounding variables equally across groups, strengthening causal conclusions.

Question 3

What is a confounding variable?

Accepted Answer

A variable that influences both the independent and dependent variables

Answer

Confounders create alternative explanations for results by simultaneously affecting the treatment and outcome.

Question 4

What is the difference between internal and external validity?

Accepted Answer

Internal validity is confidence in causal conclusions; external validity is generalizability

Answer

Internal validity ensures the study accurately identifies causal relationships, while external validity indicates how well results apply to other settings.

Question 5

What is a double-blind experiment?

Accepted Answer

Neither participants nor researchers know who receives treatment or placebo

Answer

Double-blinding prevents both participant and researcher expectations from influencing results, reducing bias.

AP Practice Test

AP Practice Test

AP Stats Experimental Design