# Standard Error

The standard error of the mean. The standard deviation divided by the square root of the number of data values. The extent to which we expect the sample mean to differ (+/-) from the population mean. The more data we have, the smaller this range becomes; but to get 10x the precision, we need 100x as much data.

**See also: **Errors, Mean, Standard Deviation, Statistic, Variance.

**Subjects: ** Statistics