Standard Deviation Calculator

Population standard deviation (σ) is used when you have data for an entire population (divides by N). Sample standard deviation (s) is used when estimating for a larger population using a representative subset (divides by N-1, Bessel's correction).

Standard deviation measures the amount of dispersion or variation in a set of values. A low standard deviation indicates that values tend to be close to the mean, while a high standard deviation indicates that values are spread out over a wider range.

Variance is the average of squared differences from the mean. Standard deviation is simply the square root of variance.

Bessel's correction uses N-1 instead of N in the denominator when calculating sample variance to correct bias in estimating population variance.