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

To increase the total sample size

Answer

To receive the most promising treatment

Answer

To observe natural behavior without any intervention

Question 2

What is random assignment and why is it important?

Accepted Answer

Randomly placing participants in groups to equalize confounding variables

Answer

Randomly selecting participants from the population

Answer

Assigning participants alphabetically

Answer

Letting participants choose their own group

Question 3

What is a confounding variable?

Accepted Answer

A variable that influences both the independent and dependent variables

Answer

Any variable measured in the study

Answer

The variable being manipulated

Answer

A variable that only affects the control group

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

They are the same concept

Answer

Internal validity only matters for lab studies

Answer

External validity is always more important

Question 5

What is a double-blind experiment?

Accepted Answer

Neither participants nor researchers know who receives treatment or placebo

Answer

Both groups receive the treatment

Answer

The experiment is repeated twice

Answer

Two different treatments are tested simultaneously

Question 6

Why is replication important in experimental research?

Accepted Answer

It confirms that findings are reliable and not due to chance or specific conditions

Answer

It is only necessary when initial results are surprising

Answer

Replication wastes resources on redundant studies

Answer

Only exact replications are valuable