Werk #5465: Fixed calculation of standard deviation.

Component

Livestatus

Title

Fixed calculation of standard deviation.

Date

Nov 24, 2017

Level

Trivial Change

Class

Bug Fix

Compatibility

Compatible - no manual interaction needed

Checkmk versions & editions

1.5.0i2	Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk MSP (CME)

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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