> For the complete documentation index, see [llms.txt](https://cortex-docs.paloaltonetworks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cortex-docs.paloaltonetworks.com/cortex-xdr-3.x/cortex-xdr-3.x-documentation/cortex-xdr-xql/functions/stddev_population.md).

# stddev\_population

**Syntax**

**comp stage**

```programlisting
comp stddev_population(<field>) [as <alias>] by <field_1>,<field_2> [addrawdata = true|false [as <target field>]]
```

**windowcomp stage**

```programlisting
windowcomp stddev_population(<field>) [by <field> [,<field>,...]] [sort [asc|desc] <field1> [, [asc|desc] <field2>,...]] [between 0|null|<number>|-<number> [and 0|null|<number>|-<number>] [frame_type=range]] [as <alias>] 
```

**Description**

The `stddev_population()` function is used to return a single population (biased) variance value of a field for a group of rows. The function syntax and application is based on the preceding stage:

**comp stage**

When the `stddev_population` aggregation function is used with a [comp](/cortex-xdr-3.x/cortex-xdr-3.x-documentation/cortex-xdr-xql/stages/comp.md) stage, the function returns a single population (biased) variance value of a field over a group of rows, for all records that contain matching values for the fields identified in the `by` clause.

In addition, you can configure whether the raw data events are displayed by setting `addrawdata` to either `true` or `false` (default), which are used to configure the final `comp` results. When including raw data events in your query, the query runs for up to 50 fields that you define and displays up to 100 events.

**windowcomp stage**

When the `stddev_population` statistical aggregate function is used with a [windowcomp](/cortex-xdr-3.x/cortex-xdr-3.x-documentation/cortex-xdr-xql/stages/windowcomp.md) stage, the function returns a single population (biased) variance value of a field for each row in the group of rows, for all records that contain matching values for the fields identified using a combination of the `by` clause, `sort`, and `between` window frame clause. The results are provided in a new column in the results table.

**Examples**

<details>

<summary>comp example</summary>

Calculates a maximum of 100 `metrics_source` records, where the `_broker_device_id` is `655AYUWF`, and include a single population (biased) variance value of the `total_size_rate` field for a group of rows.

```programlisting
dataset = metrics_source 
| filter _broker_device_id = "655AYUWF" 
| comp stddev_population(total_size_rate)
| limit 100
```

</details>

<details>

<summary>windowcomp example</summary>

Return maximum of 100 `metrics_source` records and include a single population (biased) variance value of the `total_size_rate` field for each row in the group of rows, for all records that contain matching values in the `_broker_device_id` field. The results are provided in the `stddev_population` column.

```programlisting
dataset = metrics_source
| limit 100
| windowcomp stddev_population(total_size_rate) by _broker_device_id as `stddev_population`
```

</details>


---

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