What is mean deviation? Write its two merits

"Mean deviation is the Arithmetic Average of deviations of all the values taken from a statistical average (Mean, Median or Mode) of Series. In taking deviation of values, Algebraic signs’+’ and Are not taken into consideration, i.e., neagtive deviations are also treated as positive deviations."

  1. Simple and easy to understand.
  2. Based on all the items.