juniorAnomaly Detection
How does Z-Score help in detecting outliers?
Updated May 5, 2026
Short answer
It measures how many standard deviations a point is from the mean[cite: 1].
Deep explanation
Points with a Z-score greater than 3 (or less than -3) are typically considered outliers in a normal distribution[cite: 1].
Real-world example
Finding students with exceptionally high or low test scores[cite: 1].
Common mistakes
- Applying Z-score to non-Gaussian (skewed) data[cite: 1].
Follow-up questions
- What is Modified Z-score?