E(X-μ) for X and μ Vectors: First Central Moment

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SUMMARY

The first central moment E(X-μ) for vector variables X and μ, where X ~ N(μ, σ²), is zero. This holds true even when X and μ are vectors, such as X = [x1, x2] and μ = [μ1, μ2]. The evaluation can be performed component-wise, confirming that each component results in zero, thus producing a vector of zeros.

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saintman4
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where X ~ N (μ, σ2)

I know that if X is random variable, the first central moment E(X-E(X)) = E(X-μ) is zero. But I would like to know if X and μ is vector. For example if X = [x1 x2] and μ = [μ1 μ2]. What is the value of E(X-μ)?



Thank you
 
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saintman4 said:
where X ~ N (μ, σ2)

I know that if X is random variable, the first central moment E(X-E(X)) = E(X-μ) is zero. But I would like to know if X and μ is vector. For example if X = [x1 x2] and μ = [μ1 μ2]. What is the value of E(X-μ)?

It's still zero, although now it's a vector of zeros. To see this, simply evaluate it component-wise and apply the scalar result you started with.
 

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