Let $W : [0, \infty) \to \text{Random}(\mathbb{R})$ be a D3658: Standard real Wiener process.
Let $t \in [0, \infty)$ be an D4767: Unsigned real number.
Let $t \in [0, \infty)$ be an D4767: Unsigned real number.
Then
\begin{equation}
W_t
\overset{d}{=} \text{Gaussian}(0, \sqrt{t})
\end{equation}