Standard Deviation Calculator

Calculate standard deviation, variance, and mean of a data set. Free online statistics calculator.

💡 Enter comma-separated numbers. Example: "2,4,4,4,5,5,7,9" → σ = 2.

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How Standard Deviation Works

Step-by-step guide with examples

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Formula

1. Calculate the mean (average). 2. Subtract the mean from each value and square the result. 3. Calculate the average of squared differences. 4. Take the square root = standard deviation. σ = √(Σ(xi - μ)² / N)

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Applications

• Statistical analysis and quality control. • Finance (volatility measurement). • Scientific research and experiments. • Grading and assessment.

Frequently Asked Questions

2 common questions answered

2 Questions2 AnswersClick to expand
Q1What is standard deviation?
Standard deviation measures how spread out data points are from the mean. A low SD means data is clustered near the mean; high SD means it's spread out.
Q2How to calculate standard deviation?
Find the mean, subtract each value from the mean, square the differences, average them, and take the square root.