Standard Deviation Calculator — population, sample

Công thức

\sigma = \sqrt{\frac{\sum (x_i - \mu)^2}{n}}

Population standard deviation.

s = \sqrt{\frac{\sum (x_i - \bar{x})^2}{n - 1}}

Sample standard deviation uses n − 1 (Bessel’s correction).

Enter the data and choose population if it is the whole group, or sample if it is part of a larger group.
Press Calculate.

The mean is 5 and the squared deviations add up to 32.

Variance = 32 / 8 = 4, so the standard deviation is √4 = 2.

Use population when you have every member of the group; use sample when your data is a subset used to estimate the whole.

How far values typically are from the mean. Larger means more spread out.