Explanation:
the mean value is
(63+70+68+73+58+67)/6 = 399/6 = 66.5 in
the absolute deviation (sum of the absolute values of the differences of the individual data entries to the mean value divided by the number of data points) is
(66.5-63 + 70-66.5 + 68-66.5 + 73-66.5 + 66.5-58 + 67-66.5)/6 = (3.5 + 3.5 + 1.5 + 6.5 + 8.5 + 0.5)/6 =
= 24/6 = 4 in