Definition:Constant Mean Level

Definition
Let $S$ be a stochastic process giving rise to a time series $T$.

$T$ has a constant mean level the mean of $S$ does not change as time progresses.

It is calculated as the expectation of $S$:


 * $\mu = \expect {z_t} = \displaystyle \int_{-\infty}^\infty z \map p z \rd z$

where $\map p z$ is the (constant) probability mass function of $S$.