Bessel's correction

Named after Friedrich Bessel.

Bessel's correction

1. (statistics) The use of n − 1 instead of n in the formula for the sample variance and sample standard deviation, where n is the number of observations in a sample. This corrects the bias in the estimation of the population variance and partially corrects the bias in the estimation of the population standard deviation, but often also increases the mean squared error in these estimations.