Standard Deviation Formula:
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Definition: This calculator computes the standard deviation (σ), which is the square root of variance, measuring how spread out numbers are from their mean.
Purpose: It helps statisticians, researchers, and data analysts understand the dispersion of a dataset.
The calculator uses the formula:
Where:
Explanation: The calculator first finds the mean, then calculates each point's squared difference from the mean, averages these squared differences (variance), and finally takes the square root.
Details: Standard deviation is crucial for understanding data variability, comparing datasets, and making statistical inferences.
Tips: Enter your data points as comma-separated values (e.g., "5, 10, 15, 20"). The calculator will compute all related statistics.
Q1: What's the difference between variance and standard deviation?
A: Variance is the average squared deviation from the mean, while standard deviation is its square root, in the original units.
Q2: When should I use population vs sample standard deviation?
A: This calculator uses population standard deviation (dividing by N). For sample standard deviation, divide by N-1 instead.
Q3: What does a high standard deviation indicate?
A: High σ means data points are spread out from the mean, while low σ indicates they're clustered close to the mean.
Q4: Can I use this for non-numerical data?
A: No, standard deviation requires numerical data that can be meaningfully averaged.
Q5: How many decimal places should I use?
A: Typically 2-4 decimal places, depending on your data's precision requirements.