What is the difference between population and sample standard deviation?

Population standard deviation measures the spread of an entire population, using all data points. Sample standard deviation estimates the spread of a population based on a sample, using n-1 in the denominator to correct bias. Use population when you have all data, sample when you have a subset.

How do I use the standard deviation calculator?

Enter your data values separated by commas or spaces. The calculator will compute both population and sample standard deviation, along with variance. Ensure you enter numeric values only and separate them correctly.

What does variance mean in statistics?

Variance is the average of the squared differences from the mean. It measures how far each number in the set is from the mean. Standard deviation is the square root of variance, providing a measure of spread in the same units as the data.

Mathematiques

Instantané, privé et gratuit

Calculateur d'Ecart Type.

Calculer l'ecart type de population et d'echantillon avec la variance

Calcul sur l'appareilSans inscription

Saisissez vos valeurs

Les résultats se mettent à jour pendant la saisie.

02 / RÉPONSE

Entrez des Nombres(Entrez des nombres separes par des virgules, espaces ou retours a la ligne)

Population (σ)

Ecart Type de Population (σ) : A utiliser lorsque vous avez les donnees de toute la population. Division par N.

Echantillon (s)

Ecart Type d'Echantillon (s) : A utiliser lorsque vous avez un echantillon d'une population plus grande. Division par N-1 (correction de Bessel).

Echantillon Resultats

Moyenne (μ)18.0000

Variance (s²)27.4286

Ecart Type (s)5.2372

Resultats

Effectif (n)8

Somme (Σx)144.00

Median18.5000

Mode23

Etendue13.00

Min / Max10 / 23

Donnees Triees

10, 12, 16, 16, 21, 23, 23, 23

Comprendre l'Ecart Type

Interpretation : Un ecart type faible signifie que les donnees sont proches de la moyenne. Un ecart type eleve signifie que les donnees sont dispersees sur une plage plus large.

Population vs. Echantillon: Ecart Type de Population (σ) : A utiliser lorsque vous avez les donnees de toute la population. Division par N. Ecart Type d'Echantillon (s) : A utiliser lorsque vous avez un echantillon d'une population plus grande. Division par N-1 (correction de Bessel).

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Cite this calculator

Canonical URL: https://mathify.one/fr/math/standard-deviation

Cite as: Mathify. (n.d.). Calculateur d'Ecart Type. https://mathify.one/fr/math/standard-deviation

Use Cases

Analyze test scores

Teachers and students can use the calculator to understand the spread of exam results, identifying how consistent performance is across a class.

Example: Enter scores like 85, 90, 78, 92, 88 to see the standard deviation.

Quality control in manufacturing

Engineers can measure variability in product dimensions or weights to ensure consistency and meet quality standards.

Example: Input measurements like 10.2, 10.5, 10.1, 10.3 to check process variability.

Frequently Asked Questions

What is the difference between population and sample standard deviation?: Population standard deviation measures the spread of an entire population, using all data points. Sample standard deviation estimates the spread of a population based on a sample, using n-1 in the denominator to correct bias. Use population when you have all data, sample when you have a subset.
How do I use the standard deviation calculator?: Enter your data values separated by commas or spaces. The calculator will compute both population and sample standard deviation, along with variance. Ensure you enter numeric values only and separate them correctly.
What does variance mean in statistics?: Variance is the average of the squared differences from the mean. It measures how far each number in the set is from the mean. Standard deviation is the square root of variance, providing a measure of spread in the same units as the data.

Tips & Common Mistakes

Tips

Ensure your data is numeric and separated by commas or spaces for accurate calculation.
Use population standard deviation when your data represents the entire group; use sample for a subset.
Check for outliers before interpreting standard deviation, as extreme values can inflate the result.
Remember that standard deviation is always non-negative; a value of 0 means all data points are identical.

Common Mistakes to Avoid

Confusing population and sample standard deviation, leading to incorrect conclusions.
Entering non-numeric characters or mixing delimiters, causing errors in calculation.
Using standard deviation to compare datasets with different units or scales without proper normalization.

Last updated: August 13, 2026