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This can be rephrased as follows.

Let $X$ and $Y$ be independent random variables with the same, continuous, distribution. Is it true that $E(X)\le E(|X-Y|)$.

  1. Is this likely?

  2. Is it true for a discrete distribution?

  3. If one has a discrete counterexample, can one convert it to a continuous counterexample?

Added I now realise that there was some absolute value signs in the original integral (these come out badly on my screen) and I should have written $E(|X|)\le E(|X-Y|)$. Plus ca change...

show/hide this revision's text 1 [made Community Wiki]

This can be rephrased as follows.

Let $X$ and $Y$ be independent random variables with the same, continuous, distribution. Is it true that $E(X)\le E(|X-Y|)$.

  1. Is this likely?

  2. Is it true for a discrete distribution?

  3. If one has a discrete counterexample, can one convert it to a continuous counterexample?