z-score

A z-score, also known as a standard score, indicates the number of standard deviations a data value is from the mean. It is a numerical measure used in statistics to describe the relative position of a data point within a dataset.12

The formula for calculating a z-score is:
(z = (x - \bar{x}) / s)
where:
* (x) is the data value
* (\bar{x}) is the sample mean
* (s) is the sample standard deviation2

Z-scores are particularly useful for identifying outliers, which are data values that are unusually large or small compared to the rest of the data. A common rule of thumb is that any value with a z-score less than -3 or greater than +3 can be considered an outlier.2