n
nicefa.
Advanced Proof

Derivation of the Chi-Square Distribution from Sum of Squared Standard Normal Variables

Students often struggle to differentiate between the individual standard normal variables Zi Z_i and the resulting χ2 \chi^2 variable. Remember: the Zi Z_i are symmetric about zero, but their squared sum χ2 \chi^2 is strictly non-negative, shifting the focus from location to magnitude and variability.
Institutional Reference: Applied Statistics
View Full Proof →