# ESDTEST

gts outlier

##### See also

The `ESDTEST`

function detects outliers in a GTS (or a **LIST** of GTS), by applying a generalized extreme studentized deviate test.

This test is done under the assumption that the GTS follows an approximately normal distribution.

A Grubbs’test is done for one candidate at a time. Then, the candidate is removed from the set and another Grubbs’test is performed. This process is iterated a given number of times. The detected outliers are the removed values and the current candidate of the last successful test.

A **LIST** of ticks (or a **LIST** of **LIST** of ticks), corresponding to the outliers, is pushed back onto the stack.

This function only applies to GTS of type **DOUBLE**.

Rosner, Bernard (May 1983), “Percentage Points for a Generalized ESD Many-Outlier Procedure”,Technometrics, 25(2), pp. 165-172.