Experimental Design Math Example 1
Follow the full solution, then compare it with the other examples linked below.
Example 1
mediumDesign an experiment to test whether caffeine improves test performance. Identify: explanatory variable, response variable, control group, treatment group, and how to control for confounders.
Solution
- 1 Explanatory variable (factor): caffeine consumption (with/without)
- 2 Response variable (outcome): test score
- 3 Control group: no caffeine (placebo, e.g., decaf coffee that looks identical)
- 4 Treatment group: caffeine dose
- 5 Controlling confounders: random assignment to groups (balances sleep, stress, ability); double-blind design (neither participant nor tester knows which group); same test, same time of day, same environment
Answer
Explanatory: caffeine. Response: test score. Control for confounders via random assignment and double-blinding.
Good experimental design uses (1) comparison (control vs treatment), (2) randomization (eliminates confounders), (3) replication (multiple subjects per group), and often (4) blinding (prevents bias). The double-blind design is the gold standard.
About Experimental Design
The deliberate planning of a study in which the researcher imposes treatments on subjects and measures responses, using control groups, randomization, replication, and (where possible) blinding to establish cause-and-effect relationships.
Learn more about Experimental Design →More Experimental Design Examples
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