standard error

The standard error of an estimate is a measure of the sampling variability of the estimate.

A statistical measure that indicates the predictive accuracy over all individuals of a mean value derived from a sample population.

The default output "stream" for nasty remarks that don't belong in "standard output". Represented within a Perl program by the "filehandle" "STDERR". You can use this stream explicitly, but the die and warn built-ins write to your standard error stream automatically.