Data: 9, 14, 4, 15, 18 
To find the mean deviation: 
Step 1: Find the mean of all values 
Mean of Data = (9 + 14 + 4 + 15 + 18)/5 = 12 
Step 2: Find the distance of each value from that mean (subtract the mean from each value, ignore minus signs) 
Sum of distances = (3 + 2 + 8 + 3 + 6) = 22 
Step 3: Then find the mean of those distances 
Deviation = 22 / 5 = 4.4

The quantities of apples supplied by a farmer in a week are shown below:9, 14, 4, 15, 18.The means deviation of this data is:

Earlier discussion