> ## Documentation Index
> Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# cdf()

<span id="atoti.stats.normal.cdf" />

> atoti.stats.normal.cdf(<br />
>     *point*: VariableMeasureConvertible,<br />
>     /,<br />
>     \*,<br />
>     *mean*: NumericMeasureConvertible,<br />
>     *standard\_deviation*: StrictlyPositiveNumber | VariableMeasureConvertible,<br />
> ) → MeasureDefinition

Cumulative distribution function for a normal distribution.

<Warning>
  This feature is [`experimental`](./atoti.experimental#atoti.experimental), its key is `"stats.normal.cdf"`.
</Warning>

The cdf is given by the formula

$$
\operatorname {{cdf}}(x) = \frac {{1}}{{2}}\left[1 + \operatorname {{erf}} \left(\frac {{x-\mu }}{{\sigma {{\sqrt {{2}}}}}}\right)\right]
$$

Where $\mu$ is the mean of the distribution, $\sigma$ is its standard deviation and $\operatorname {{erf}}$ the error function.

### Parameters

<h4 id="atoti.stats.normal.cdf.point">
  *point*
</h4>

The point where the function is evaluated.

<h4 id="atoti.stats.normal.cdf.mean">
  *mean*
</h4>

The mean value of the distribution.

<h4 id="atoti.stats.normal.cdf.standard_deviation">
  *standard\_deviation*
</h4>

The standard deviation of the distribution.
Must be positive.

***

<Callout icon="link">
  **See also**:
  [cdf of a normal distribution](https://en.wikipedia.org/wiki/Normal_distribution#Cumulative_distribution_function).
</Callout>