# stdevOver


The `stdevOver` function calculates the standard deviation of the specified measure, partitioned by the chosen attribute or attributes, based on a sample. 

## Syntax


The brackets are required. To see which arguments are optional, see the following descriptions.

```
stdevOver
(
      measure 
     ,[ partition_field, ... ] 
     ,calculation level 
)
```

## Arguments


*measure*   
The measure that you want to do the calculation for, for example `sum({Sales Amt})`. Use an aggregation if the calculation level is set to `NULL` or `POST_AGG_FILTER`. Don't use an aggregation if the calculation level is set to `PRE_FILTER` or `PRE_AGG`.

 *partition field*   
(Optional) One or more dimensions that you want to partition by, separated by commas.   
Each field in the list is enclosed in \$1\$1 (curly braces), if it is more than one word. The entire list is enclosed in [ ] (square brackets).

 *calculation level*  
(Optional) Specifies the calculation level to use:  
+ **`PRE_FILTER`** – Prefilter calculations are computed before the dataset filters.
+ **`PRE_AGG`** – Preaggregate calculations are computed before applying aggregations and top and bottom *N* filters to the visuals.
+ **`POST_AGG_FILTER`** – (default) table calculations are computed when the visuals display. 
This value defaults to `POST_AGG_FILTER` when blank. For more information, see [Using level-aware calculations in Quick](https://docs.amazonaws.cn/quicksight/latest/user/level-aware-calculations.html).

## Example


The following example calculates the standard deviation of `sum(Sales)`, partitioned by `City` and `State`, based on a sample..

```
stdevOver
(
     sum(Sales), 
     [City, State]
)
```

The following example calculates the standard deviation of `Billed Amount` over `Customer Region`, based on a sample. The fields in the table calculation are in the field wells of the visual.

```
stdevOver
(
     sum({Billed Amount}),
     [{Customer Region}]
)
```