Werk #5465: Fixed calculation of standard deviation.

Component Livestatus
Title Fixed calculation of standard deviation.
Date Nov 24, 2017
Checkmk Edition Checkmk Raw (CRE)
Checkmk Version 1.5.0i2
Level Trivial Change
Class Bug Fix
Compatibility Compatible - no manual interaction needed

Note: This fixes only a slightly esoteric feature, namely "Stats: std ..." headers. Normal users are not affected, only those using this header via self-written scripts.

Livestatus incorrectly used a bias correction when calculating the standard deviation. For more mathematical background see:

https://en.wikipedia.org/wiki/Bessel%27s_correction http://mathworld.wolfram.com/StandardDeviation.html

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