Standard Deviation Calculator
Free online standard deviation calculator. Calculate mean, variance, and standard deviation for population and sample data sets.
Standard Deviation Calculator
Separate numbers with commas, spaces, or newlines.
Descriptive Statistics
Count (N):8
Sum (Σx):144
Mean (μ):18
Population (Entire Group)
Standard Deviation (σ):4.8989795
Variance (σ²):24
Sample (Subset of Group)
Sample Standard Deviation (s):5.2372294
Sample Variance (s²):27.428571
What is Standard Deviation?
Standard deviation is a statistical measure that tells you how dispersed or spread out the numbers in a dataset are from the mean (average).
- Low Standard Deviation: The data points tend to be very close to the mean.
- High Standard Deviation: The data points are spread out over a large range of values.
Population vs. Sample
It is crucial to know whether your dataset represents an entire Population or just a Sample (a subset) of the population.
- Population Standard Deviation (σ): Used when you have data for every single member of the group you are studying. Formula divides by
N. - Sample Standard Deviation (s): Used when you only have a sample of the population. Formula divides by
N - 1(Bessel's correction) to provide an unbiased estimator.