Editing Central moment (section)

==Central moment of complex random variables==
The {{mvar|n}}-th central moment for a complex random variable {{mvar|X}} is defined as <ref>{{cite book | last1 = Eriksson | first1 = Jan | last2 = Ollila | first2 = Esa | last3 = Koivunen | first3 = Visa | title = 2009 IEEE International Conference on Acoustics, Speech and Signal Processing | chapter = Statistics for complex random variables revisited | doi = 10.1109/ICASSP.2009.4960396 | pages = 3565–3568 | year = 2009 | isbn = 978-1-4244-2353-8 | s2cid = 17433817 }}</ref>
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|equation = <math>\alpha_n = \operatorname{E} \left[ {\left( X - \operatorname{E}[X] \right)}^n \right],</math>
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The absolute {{mvar|n}}-th central moment of {{mvar|X}} is defined as
{{Equation box 1
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|equation = <math>\beta_n = \operatorname{E} \left[ {\left|\left( X - \operatorname{E}[X] \right)\right|}^n \right].</math>
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The 2nd-order central moment {{math|''β''<sub>2</sub>}} is called the [[Complex random variable#Variance and pseudo-variance|''variance'']] of {{mvar|X}} whereas the 2nd-order central moment {{math|''α''<sub>2</sub>}} is the [[Complex random variable#Variance and pseudo-variance|''pseudo-variance'']] of {{mvar|X}}.