Guide to Using the Standard Deviation Calculator
Compute the standard deviation, variance, and range of a data set with the option of population or sample statistics. For each value, computes the distance from the mean to the sample, then averages squared differences and takes the square root. CalcTracker provides this free online calculator for instant, precise, and detailed computations without requiring any sign-up or software installation. All calculations run locally in your browser to guarantee complete user privacy and 100% offline accessibility.
Standard Deviation Formula
SD = sqrt(sum((xi - mean)^2) / n) (population)
Variance is the mean squared deviation; standard deviation is its square root, expressed in the same unit as the data.
Example
- Data set 2,4,4,4,5,5,7,9: mean is 5, standard deviation (population) is 2.
⚠ Note
- Decide between population (divide by n) and sample (divide by n-1) statistics carefully.
Frequently Asked Questions (FAQ)
Q: Should I use population or sample SD?
Use sample (n-1) when your data is a sample of a larger population.