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Trimmed Mean

The trimmed mean is the average value of a series excluding the smallest and biggest points.

Netdata applies linear interpolation on the last point, if the percentage requested to be excluded does not give a round number of points.

The following percentile aliases are defined:

  • trimmed-mean1
  • trimmed-mean2
  • trimmed-mean3
  • trimmed-mean5
  • trimmed-mean10
  • trimmed-mean15
  • trimmed-mean20
  • trimmed-mean25

The default trimmed-mean is an alias for trimmed-mean5. Any percentage may be requested using the group_options query parameter.

how to use

Use it in alerts like this:

 alarm: my_alert
on: my_chart
lookup: trimmed-mean5 -1m unaligned of my_dimension
warn: $this > 1000

trimmed-mean does not change the units. For example, if the chart units is requests/sec, the result will be again expressed in the same units.

It can also be used in APIs and badges as &group=trimmed-mean in the URL and the additional parameter group_options may be used to request any percentage (e.g. &group=trimmed-mean&group_options=29).


Examining last 1 minute successful web server responses:


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