Data set: 30, 35, 35, 40, 55
Mean: (30 + 35 + 35 + 40 + 55) / 5 = 195/5 = 39
30 - 39 = -9
35 - 39 = -4
35 - 39 = -4
40 - 39 = 1
55 - 39 = 16
Because we are looking for absolute deviation, this means that we disregard the negative sign of the numbers.
(9 + 4 + 4 + 1 + 16)/5 = 34/5 = 6.8
The Mean Absolute Deviation is 6.8