Statistics and probability
Standard deviation
The square root of variance, measuring the typical spread of observations around their mean in the original units.
In one sentence
What does Standard deviation mean?
The square root of variance, measuring the typical spread of observations around their mean in the original units.
How it is written
σ=√(Σ(xᵢ−μ)²/N)
A compact example
A dataset whose values cluster near the mean has a smaller standard deviation.
Other names and search terms
SD.
Where this fits
When should you learn Standard deviation?
The first encounter is not the final level. Many ideas begin visually, become computational in high school and become formal in college.
- 1Pre-high schoolPrepare foundations
- 2High schoolUsually introduced
- 3CollegeGreater depth
- 4AdvancedGreater depth
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Questions about Standard deviation
What does Standard deviation mean in mathematics?
The square root of variance, measuring the typical spread of observations around their mean in the original units.
How is Standard deviation written?
A common notation is σ=√(Σ(xᵢ−μ)²/N).
What is an example of Standard deviation?
A dataset whose values cluster near the mean has a smaller standard deviation.