Below are the distances from Jamar's house to each of the four restaurants in his town (in kilometers). A rectangle made up by four identical rectangles. They make up 2 columns and 2 rows. The first row values are as follows: 4 tenths, 2 tenths. The second row values are as follows: 4 tenths, 6 tenths. Find the mean absolute deviation (MAD) of the data set.