> ## 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.

# atoti.stats.normal.cdf()

### atoti.stats.normal.cdf(point, /, \*, mean, standard\_deviation)

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:**
  * **point** (*VariableMeasureConvertible*) – The point where the function is evaluated.
  * **mean** (*NumericMeasureConvertible*) – The mean value of the distribution.
  * **standard\_deviation** (*StrictlyPositiveNumber* *|* *VariableMeasureConvertible*) – The standard deviation of the distribution.
    Must be positive.
* **Return type:**
  MeasureDefinition

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