Glossary · Phase 2 · Math, when you need it
Standard deviation
The typical distance of a value from the average. It is the square root of the variance.
Try it now
Same mean, different spread. Drag the standard deviation (σ) and draw samples. A larger σ means single results land farther from the average.
Learn it properly
Mean, variance and spread · Expected value, variance and standard deviation. About 25 minutes.
Other terms from the same lesson
- expected value: The long-run average of a random amount: each value times its chance, all added up.
- mean: The average: add the values up and divide by how many there are.
- variance: How spread out values are around their average.
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