University of Virginia

Journal Club

Mean and Standard Deviation Demonstration

Created by Thomas Hartka, MD, MS, MSDS

2/6/2026

This interactive demonstration shows why mean and standard deviation are only appropriate for normally distributed data.

Exercise 1: Galton Board

Watch balls fall through pegs to create a normal distribution

Exercise 2: Normal Distribution

Explore samples from a normal distribution

Exercise 3: Lognormal Distribution

See why mean and SD are inappropriate for non-normal data