I wish to clarify upfront I am looking for a way to calculate Standard deviation using Streams (I have a working method at present which calculates & returns SD but without using Streams).

The dataset i am working with matches closely as seen in [Link](https://stackoverflow.com/questions/26340688/group-by-and-sum-objects-like-in-sql-with-java-lambdas/26341146#26341146). As shown in this link am able to group my data & get the average but not able to figure out how to get the SD.

***Code***

```
outPut.stream()
            .collect(Collectors.groupingBy(e -> e.getCar(),
                    Collectors.averagingDouble(e -> (e.getHigh() - e.getLow()))))
            .forEach((car,avgHLDifference) -> System.out.println(car+ "\t" + avgHLDifference));

```

I also checked [Link](https://groups.google.com/forum/#!topic/javaposse/B1t-ViNSXGw) on DoubleSummaryStatistics but it doesn't seem to help for SD.