Population and sample standard deviation formulas side by side, for quick reference.
Population and sample standard deviation formulas side by side. For the full worked example, see What Is Standard Deviation?.
Use population standard deviation when your data covers an entire group of interest; use sample standard deviation when your data is a sample meant to estimate a larger population.
The Standard Deviation Calculator calculates both instantly for any data set.
Standard Deviation Calculator
Population if your data is the entire group you care about; sample if it’s a subset representing a larger population.
It corrects for the tendency of a sample to underestimate the true population variance.
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