# Median

The median is the value separating the higher half from the lower half of a data sample (a population or a probability distribution). For a data set, it may be thought of as the "middle" value.

`median`

is not an accurate average. However, it eliminates all spikes, by sorting
all the values in a period, and selecting the value in the middle of the sorted array.

Netdata also supports `trimmed-median`

, which trims a percentage of the smaller and bigger values prior to finding the
median. The following `trimmed-median`

functions are defined:

`trimmed-median1`

`trimmed-median2`

`trimmed-median3`

`trimmed-median5`

`trimmed-median10`

`trimmed-median15`

`trimmed-median20`

`trimmed-median25`

The function `trimmed-median`

is an alias for `trimmed-median5`

.

## how to use

Use it in alerts like this:

` alarm: my_alert`

on: my_chart

lookup: median -1m unaligned of my_dimension

warn: $this > 1000

`median`

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=median`

in the URL. Additionally, a percentage may be given with
`&group_options=`

to trim all small and big values before finding the median.

## Examples

Examining last 1 minute `successful`

web server responses:

## References

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