Standard Deviation Calculator
Understanding Standard Deviation
Standard deviation measures how spread out data is from the mean. A low standard deviation means data points are close to the mean. High standard deviation indicates more variability.
Key Concepts
- Population: All data points (divides by N)
- Sample: Subset of population (divides by N-1)
- 68-95-99.7 Rule: Normal distribution percentages
💡 Tips
- Low SD = consistent data
- High SD = variable data
- Use sample SD for estimates
- Outliers increase SD