ZscoreActor

The ZscoreActor (Z-score actor) is a Coral Actor that determines whether or not a value from an event is an outlier. The statistics actor state is used for the average and standard deviation of the measurement value.

Creating the actor

The creation JSON of the z-score actor (see Coral Actor) has type: "zscore". The params value is a JSON with a single field:

field	type	required	description
`by`	string	yes	the name of the grouping field
`field`	string	yes	the name of measurement field
`score`	float	yes	the value of the threshold for outliers

Example

{
  "data": {
    "type": "actors",
    "attributes": {
      "type": "zscore",
      "params": {
        "by": "tag",
        "field": "amount",
        "score" : 6.0
      }
    }
  }
}

This will create a Z-score component monitoring the field amount. Outliers are defined to be more than 6 sd from the average.

Trigger

The ZscoreActor accepts as trigger a JSON with a value for the specified field.

Emit

The ZscoreActor emits the input but only when the value is considered an outlier (see below)

State

The ZscoreActor keeps no state.

Collect

The ZscoreActor collects state from the StatsActor for the field it monitors. The count, average and standard deviation values are used to determine whether or not the trigger value is an outlier.

Timer

The ZscoreActor does not provide timer actions.

CORAL WIKI

Actors

Getting started

Overview