Courses/Behavioral Research: Statistical Methods

Behavioral Research: Statistical Methods

CG3.402

Vinoo Alluri•Monsoon 2025-26•4 credits

Revision Notes/Unit 7 — Hypothesis Testing & NHST

Unit 7 — Hypothesis Testing & NHST

Steps of NHST, Type I (α) and Type II (β) errors, statistical power (1 − β), Cohen's d, sample-size planning, one- vs two-tailed tests, t-tests (one-sample, independent, paired, Welch).

p-values, Errors, Power, t-tests

13 min

NHST is the workhorse of inferential statistics. Set up a **null hypothesis** ('no effect'); compute a test statistic; ask **'how surprising would these data be if H₀ were true?'** (the **p-value**); reject H₀ if p < α. **Type I error (α)** = false alarm; **Type II error (β)** = missed real effect. **Power = 1 − β** depends on n, effect size, α, variance, design. Falsifiability (Popper) is the philosophical foundation — we can never prove H₀, only fail to reject it. **Always report effect size + CI alongside p.**