Average Deviation from the Mean (Population): Given a population data set \(x_1, x_2, ... , x_n\) with mean \(\mu\) each term deviates from the mean by the value \(x_k - \mu\text{.}\) So, averaging these gives
\begin{equation*}
\frac{\sum_{k=1}^n (x_k-\mu)}{n} = \frac{\sum_{k=1}^n x_k}{n} - \frac{\sum_{k=1}^n \mu}{n} = \mu - \mu = 0.
\end{equation*}
This metric is therefore always zero for any provided set of data since cancellation makes this not useful. You should have expected this to be true since the definition of the mean is indeed the place where the data is "balanced". So, we need to determine ways to avoid cancellation.