Answer:
4.32
Step-by-step explanation:
First, we have to find the mean of the data set.
16, 11, 9, 12, 11, 10, 10, 8, 15, 0, 2, 15, 14, 7, 11, 5, 14, 20, 3, 11, 13, 7, 0, 5, 21 all added together equals 250. 250 divided by 25 = 10. So 10 is the mean.
Now we have to find the absolute distances of each number from the mean.
16 - 10 = 6... 11 - 10 = 1... so on, giving us this -->
6, 1, 1, 2, 1, 0, 0, 2, 5, 10, 8, 5, 4, 3, 1, 5, 4, 10, 7, 1, 3, 3, 10, 5, 11
Finally, we have to find the mean of the distances (which is done by adding all the numbers above and dividing the sum by the number of values there are).
108 divided by 25 = 4.32.
So, 4.32 is the mean absolute deviation (MAD) of the following data set.
is symmetric if 
. We have
is indeed symmetric.