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<!--
title: "Median"
sidebar_label: "Median"
description: "Use median in API queries and health entities to find the 'middle' value from a sample, eliminating any unwanted spikes in the returned metrics."
custom_edit_url: https://github.com/netdata/netdata/edit/master/web/api/queries/median/README.md
learn_status: "Published"
learn_topic_type: "References"
learn_rel_path: "Developers/Web/Api/Queries"
-->
# 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:
- ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=min&after=-60&label=min)
- ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=average&after=-60&label=average)
- ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=median&after=-60&label=median&value_color=orange)
- ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=max&after=-60&label=max)
## References
- <https://en.wikipedia.org/wiki/Median>.
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