A large MAD is the mean absolute deviation of a set. It shows swimmers the average distance between the observed data values and the mean. A MAD chart can be used to predict future swim results for many reasons. However, its primary purpose is to tell swimmers how far they are away from the mean. The average is calculated by ordering data from lowest to most important and then dividing it by the number observations.
Students need to understand that the MAD (middle interval between data values and mean) is a distance between data values. They should also know that MAD is a way to compare class data. The student should discuss the results and explain their reasoning. The smaller the MAD, the closer the data are to the mean, and the better the mean is as a descriptor. Students who aren’t organized are more likely to make MAD errors. It is a good idea for students to write data values in one column and distances from the median in another column.