So we want to know what MAD from this set of data is that has the mean value of 4. First we determine the distance d of each number from the set from the mean value: d1=4-3=1, d2=4-4=0, d3=5-4=1, d4=6-4=2. So our set of distances is {1,1,1,1,0,0,0,1,1,2}. Now we can determine MAD: MAD=(1+1+1+1+0+0+0+1+1+2)/10=0.8.
