Show that for ANY data set, the sum of the positive deviations from the eman must be exactly equal to the sum of negative deviations from the mean?

I can work this out when subbing in values, but can anyone prove it with formulae?

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- March 20th 2009, 11:23 PMmibamarsPositive Deviations = Negative Deviations?
Show that for ANY data set, the sum of the positive deviations from the eman must be exactly equal to the sum of negative deviations from the mean?

I can work this out when subbing in values, but can anyone prove it with formulae? - March 22nd 2009, 05:25 AMHallsofIvy
I presume that by "deviation from the mean" you mean simply the value minus the mean.: . Mean itself is defined by so the sum of deviations is . But is a constant so . Putting those together, . Since that sum is 0, the negative values and positive values must cancel.