Central Limit Theorem
Six Sigma
Central Limit Theorem (CLT)
Central Limit Theorem
Principle that the distribution of sample means tends toward normality as sample size grows under broad conditions.
Examples
- 01Because of the central limit theorem, the Green Belt can use an X-bar chart for averages of 5 parts, even though single fill weights are skewed.
- 02During Measure, the team checks the central limit theorem in practice by plotting subgroup means, which look normal while single values do not.
- 03The project report notes that the central limit theorem justifies the normal-based control limits used in the control plan.