The graph shows a highlighted section between $x = 2$ and $x = 3$, inclusive on both endpoints. This is represented by the solid dots at both 2 and 3, indicating that these points are included in the solution set.

From this, the correct set notation should include both $x = 2$ and $x = 3$ as boundaries with $\leq$ and $\geq$.

Thus, the correct choice is:
$\{ x \mid 2 \leq x \leq 3 \}$

This set means that $x$ is greater than or equal to 2, and less than or equal to 3.

Would you like further details or explanations?

Here are 5 questions related to this topic:

1. What does it mean when a dot is solid on a number line?
2. How do we represent an open interval on a graph?
3. Can you explain the difference between "and" and "or" in set notation?
4. How do we convert set notation to interval notation?
5. What kind of inequality would describe a union of two intervals?

Tip: Solid dots on a number line mean that the endpoints are included in the interval (using $\leq$ or $\geq$).