Sample Standard Deviation Formula:
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The sample standard deviation (s) measures the dispersion of data points in a sample relative to their mean. It's the square root of the sample variance and indicates how spread out the values are.
The calculator uses the sample standard deviation formula:
Where:
Explanation: The formula calculates the square root of the average squared deviations from the mean, using n-1 (Bessel's correction) for unbiased estimation.
Details: Standard deviation is crucial in statistics for measuring variability. It's used in hypothesis testing, confidence intervals, quality control, and risk assessment.
Tips: Enter numeric values separated by commas (e.g., 5, 8, 12, 6, 9). At least two values are required. Non-numeric entries will be ignored.
Q1: Why use n-1 instead of n in the denominator?
A: Using n-1 (Bessel's correction) provides an unbiased estimate of the population standard deviation from a sample.
Q2: What's the difference between sample and population standard deviation?
A: Population standard deviation uses n in the denominator and is used when you have all data points. Sample standard deviation uses n-1 for samples.
Q3: When should I use standard deviation?
A: Use it when you need to measure dispersion in normally distributed data. For skewed distributions, consider interquartile range.
Q4: What does a high standard deviation indicate?
A: High standard deviation means data points are spread out widely from the mean, indicating high variability.
Q5: How is standard deviation related to variance?
A: Standard deviation is the square root of variance. SD has the same units as the original data, making it more interpretable.