Mean Absolute Deviation M.A.D.
The mean absolute deviation describes the average distance from the
mean for the numbers in the data set.
Step 1Find the mean of the data set.
Example:
6, 7, 7, 8, 10, 15, 17
Mean= 10
Step 2Find the absolute value of the difference between the value and
the mean. *hint= think of how far apart the numbers are on a
number line.
Example:
/6-10/= 4
/7-10/= 3
/8-10/= 2
/15-10/= 5
/7-10/= 3
/10-10/= 0
/17-10/= 7
Step 3Add your answers from Step 2 and divide by total number of
values.
Example:
4 + 3 + 3 + 2 + 0 + 5 + 7 = 24
24 ÷ 7 = 3.4
Answer The mean absolute deviation of this data set is 3.4.
The closer the number is to 0, the more consistent the data is.
Practice Calculating the Mean Absolute Deviation
Show all of your work! You may use a calculator 
1. Calculate the mean deviation for the numbers: 75, 83, 96, 100, 121 and 125
2. Ten friends scored the following marks in their end-of-year math exam:
23%, 37%, 45%, 49%, 56%, 63%, 63%, 70%, 72% and 82%
What was the mean deviation of their marks?