To find the mean absolute deviation of the data you provided, you need to find the mean first. You add all the points together to get 138. Then you divide that number by how many points there are which there are 6 points so you divide 138 by 6 to get 23. Then you calculate how far away each data point is from the mean using positive distances. These are called absolute deviations. Once you add up all the numbers to get 24, you divided them by how many points there are which is 6 again. You should get 4 in the end.
