\begin{definition}[Definition:Sample Mean of Stochastic Process]
Let $S$ be a stochastic process giving rise to a time series $T$.
The '''sample mean''' of $S$ over a set of $N$ successive values $\set {z_1, z_2, \dotsb, z_N}$ is defined as:
:$\overline z := \dfrac 1 N \ds \sum_{t \mathop = 1}^N z_t$
\end{definition}