We have, 7, 8, 4, 13, 9, 5, 16, 18
Mean of the given data is
\(\overline{X}\) = \(\frac{7+8+4+13+9+5+16+18}{8}\) = \(\frac{80}{8}\) = 10
The respective absolute values of the deviations from the mean , i.e. |Xi - \(\overline{X}\)| are 3, 2, 6, 3, 1, 5, 6, 8
Thus, the required mean deviation about the mean is
M.D. (\(\overline{x}\)) = \(\frac{\Sigma^8_{i=1}|X_1-\overline X|}{8}\)
= \(\frac{3+2+6+3+1+5+6+8}{8}\) = \(\frac{34}{8}\) = 4.25
