Let $X_t$ be defined as
$$ X_t = X_0+\int_0^t\sigma_{0}\,dW_s, $$
where $W_s$ is a Wiener process and $\sigma_0\in\mathbb{R}^{+}/{0}$. Which is the probability
$$ \mathbb{P}\left[a<X_t-X_0<b\right] ? $$
Let $X_t$ be defined as
$$ X_t = X_0+\int_0^t\sigma_{0}\,dW_s, $$
where $W_s$ is a Wiener process and $\sigma_0\in\mathbb{R}^{+}/{0}$. Which is the probability
$$ \mathbb{P}\left[a<X_t-X_0<b\right] ? $$
$\int_0^1 \sigma_0 dW_s = \sigma_0 W_t$ is a centered normal variable with variance $\sigma_0^2t$