Need don’t understand what this is the mean absolute deviation of mrs. jamison’s class is 0.24. what does this mean? explain

Mean absolute deviation is the mean of the numbers and then the mean of that. 
Example: The data set 1,2,3,4,5,6 has mean of 3.5 now you subtract the mean from all the numbers in the data set thus getting the following, 2.5,1.5,.5, .5 , 1.5, 2.5. Then you find the mean of those numbers thus getting the mean absolute deviation. 

Hope this ; )