# Reply To: What is standard deviation?

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February 19, 2017 at 8:03 pm
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SD is one of the most valuable pieces of information that you can get from the chrony. It’s nice to know both SD and ES. But I usually ignore the ES, as SD tells me a lot more.

Example:

Assume two 10-shot strings.

10 shot string #1:

ES=**44fps**

SD=**14fps**

Average=**800fps**

10 shot string #2:

ES=**40fps**

SD=**20fps**

Average=**800fps**

SD is a better indicator of shot string quality and hit probability.

If shooting a difficult field target, a gun yielding string #1 will likely give a much higher target hit rate than a gun yielding string #2. That is an extreme example, but it still holds for examples with lower ES and lower SD.

SD is one of the most valuable pieces of information that you can get from the chrony. It's nice to know both SD and ES. But I usually ignore the ES, as SD tells me a lot more.
Example:
Assume two 10-shot strings.
10 shot string #1:
ES=

**44fps**SD=**14fps**Average=**800fps**10 shot string #2: ES=**40fps**SD=**20fps**Average=**800fps**SD is a better indicator of shot string quality and hit probability. If shooting a difficult field target, a gun yielding string #1 will likely give a much higher target hit rate than a gun yielding string #2. That is an extreme example, but it still holds for examples with lower ES and lower SD.