Mention any two merit and two demerit of mean deviation

Dear Student

Merits of Mean Deviation:
(a) Mean deviation is easy to calculate and simple to understand.
(b) It is based on all observations of the series.
Demerits of Mean Deviation:
(a) It is not a popular measure as the signs are ignored in the calculation of mean deviation.
(b) If extreme values are present, then mean deviation from mean could be very different from mean deviation from the median
Regards