Variance Calculator
Variance calculator
Compute sample or population variance.
Result
4
Uses divisor n.
spread summary
Spread bars
Advanced options
Advanced insights
Variance snapshot
Population (n)
Count (n)
8
Mean
5
Range
7
Value spread preview
Formula
Population variance sum((x-mean)^2)/N sample variance sum((x-mean)^2)/(N-1) Symbol legend
| Symbol | Meaning | Unit | Copy |
|---|---|---|---|
\sigma^2 | Population variance | squared data unit | |
s^2 | Sample variance | squared data unit | |
N | Number of values | count |
- Compute mean of the dataset first.
- Sum squared deviations from mean.
- Divide by N for population or N minus 1 for sample.
Example
Worked example: 2, 4, 4, 4, 5, 5, 7, 9
- 1 Mean = 5
- 2 Squared deviation sum = 32
- 3 Population variance = 32/8 = 4
Population variance is 4.
How
- Enter dataset values.
- Choose sample or population variance mode.
- Read variance output with correct divisor.
Avoid
- Using sample divisor for full-population data.
- Skipping squaring step in deviation sum.
- Expecting variance unit to match original unit.
Checks
Best fit
Variance Calculator is built for calculate sample or population variance from numeric data for spread analysis and model inputs. If Variance Calculator does not match the input scope, compare the answer with a second method.
Input check
Check \sigma^2 before calculating: it means population variance and is measured in squared data unit.
Sanity check
For Variance Calculator, use the worked example as a quick benchmark: Population variance is 4. If the variance calculator answer is far away, check whether an input, unit, or mode changed.
Before copying
Review this common issue first: using sample divisor for full-population data.
FAQ
Why is variance unit squared?
Because deviations are squared before averaging.
How is variance related to standard deviation?
Standard deviation is the square root of variance.
When should I use sample variance?
Use sample mode when data is a sample from a larger population.
Switch
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