Courses/Behavioral Research: Statistical Methods

Behavioral Research: Statistical Methods

CG3.402

Vinoo Alluri•Monsoon 2025-26•4 credits

Revision Notes/Unit 1 — Why Do Statistics? (Biases & Base Rates)

Unit 1 — Why Do Statistics? (Biases & Base Rates)

Why human intuition is unreliable for probabilistic reasoning, the biases statistics protects against (belief bias, confirmation bias, Simpson's paradox, base-rate fallacy), and Bayes' rule as the formal corrective.

The Case for Statistics — Biases, Base Rates, Bayes

12 min

Statistics exists because **humans are wired to deceive themselves about probability**. We accept invalid arguments when the conclusion sounds right (belief bias), look only for confirming evidence (confirmation bias), aggregate over confounded subgroups and reverse the truth (Simpson's paradox), and ignore base rates when a 'positive test' arrives (base-rate fallacy). Statistics is the formal corrective: a discipline for figuring out whether what looks true is actually true. **Bayes' rule is the central operator** — the formula that rescues us from the base-rate fallacy and many others.