(singular) is used to indicate the result of applying a statistical algorithm
to a set of data
. In the calculation of the arithmetic mean
, for example, the algorithm directs us to sum all the data values and divide by the number of data items. In this case, we call the mean a statistic. To be complete in describing any use of a statistic, one must describe both the procedure and the data set.
The popular use of the term to mean a single measurement, or datum, differs from this meaning. A statistician would normally call an individual person's height a statistic only if that person were chosen randomly from some population of interest, but more often would use the term to refer to, for example, the median height of a group of people.
See also: statistics and statistical theory