Math
How to Calculate Standard Deviation: Sample vs Population
Just ask and get Editorial Team(Statistical Science)
Updated 2026-09-19
7 min read
Key Takeaway:Measure data spread and volatility around the mean with standard deviation and variance.
What Does Standard Deviation Tell You?
Standard deviation measures how dispersed the values in a dataset are relative to the mean. A low value indicates numbers cluster closely to the average; a high value indicates wide dispersion.
Frequently Asked Questions
What is the empirical 68-95-99.7 rule?
In a normal bell-curve distribution, 68% of data falls within 1 standard deviation, 95% within 2 deviations, and 99.7% within 3 deviations of the mean.