The population standard deviation is 2.
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Standard Deviation Calculator
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Standard deviation details
Formula & disclaimer
Population Variance = Σ(x − mean)² ÷ N; Sample Variance = Σ(x − mean)² ÷ (N − 1); Standard Deviation = √Variance
View assumptionsFormula reviewCalcs at Hand Editorial TeamVerified 28 August 2026 · automated checks included
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How to read this result
Three useful checks, kept deliberately short.
Population values 2, 4, 4, 4, 5, 5, 7 and 9: Calculate the mean · Square each difference from the mean · Average the squared differences and take the square root.
Use sample when the data is a subset used to estimate a larger population.
Formula and assumptions
Population Variance = Σ(x − mean)² ÷ N; Sample Variance = Σ(x − mean)² ÷ (N − 1); Standard Deviation = √VarianceUse population when the data includes every member of the group being described.
Keep in mind: Choose the data-set type that matches the question before interpreting the result.
Produced byCalcs at Hand Editorial Team
Last formula check28 August 2026
Review methodKnown examples + boundary cases
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