---
title: standardDeviation
framework: metrickit
role: symbol
role_heading: Instance Property
path: metrickit/averagestatistics/standarddeviation
---

# standardDeviation

The standard deviation of the distribution of values used to calculate the average.

## Declaration

```swift
let standardDeviation: Double?
```

## Mentioned in

Analyzing app performance with MetricKit

## Discussion

Discussion This value is nil when the standard deviation is not available.

## See Also

### Statistics

- [average](metrickit/averagestatistics/average.md)
- [count](metrickit/averagestatistics/count.md)