Courses/Behavioral Research: Statistical Methods

Behavioral Research: Statistical Methods

CG3.402

Vinoo Alluri•Monsoon 2025-26•4 credits

Revision Notes/Unit 5 — Descriptive Statistics

Unit 5 — Descriptive Statistics

Central tendency (mean, median, mode — robustness to outliers), dispersion (range, IQR, variance, SD, MAD), standardisation (z-scores), and Bessel's correction.

Centre, Spread, Standardisation

10 min

Three measures of **centre**: mean (centre of mass, sensitive), median (50th percentile, robust), mode (most-frequent, for nominal). Three measures of **spread**: range (fragile), IQR / MAD (robust), variance / SD (parametric standard, sensitive). **Standardise** with z-scores to compare across scales. Choice of measure is constrained by the **variable scale** (NOIR) and the **distribution shape** (skew, outliers, bimodality).