[Math] Can you really tell the relationship between mean and median in a skewed graph

statistics

In two old statistics textbooks, I found the following pictures:-
graphs of distributions
Without any explanation, they both inferred the following:-

When it is right skewed (as in fig. 3.2), mean > median. (And is the otherwise for the left skewed.)

  1. I wonder if the claim is always true?
  2. If it is, is there any simple proof? [By simple, I mean something like by inspection or simple logical reasoning but not deep into the statistical theory please.]

Best Answer

This claim is false. Here's an interesting article on the subject: Mean, Median, and Skew: Correcting a Textbook Rule

Also note that you shouldn't confuse the terms skew with nonparametric skew, for which your claim is true by definition.

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