Which of the following is NOT a property of Arithmetic mean (A.M)?

Σ (X - $\overline{X}$) = 0

The correct answer is option 1: Σ (X - $\overline{X}$) = 0

Two interesting properties of A.M. are:

(i) the sum of deviations of items about arithmetic mean is always equal to zero. Symbolically, Σ ($\overline{X}$ – X ) = 0.

(ii) arithmetic mean is affected by extreme values. Any large value, on either end, can push it up or down.