Find the variance of a data set, both sample and population, with the standard deviation. Enter the numbers separated by commas.
Usage Tip
Variance is in squared units, which is why standard deviation (its square root, in the original units) is usually reported.
Sample divides by n − 1; population divides by n
It is the square of the standard deviation, and underlies much of statistics.
Sample variance (n − 1) is the default; population variance (n) is shown.
The square root of variance is the standard deviation.
Variance measures how far the values in a data set typically sit from their mean. It is found by averaging the squared differences from the mean, and the standard deviation is its square root, which brings the result back to the original units of the data.
The sample and population versions differ in the divisor. The population variance divides by the number of values, while the sample variance divides by one less than that. Use the sample version when your data is only a part of a larger group, which is the usual case, and the population version when you have every value. A variance of zero means all the values are identical.