1. The problem asks to find the amplitude of the sinusoidal function shown in the graph. 2. The amplitude of a sinusoidal function $f(x) = A \sin(Bx + C) + D$ or $f(x) = A \cos(Bx + C) + D$ is the absolute value of the coefficient $A$, which represents the maximum distance from the midline (center) to a peak or trough. 3. From the graph description, the sinusoidal function oscillates between $y = 1$ and $y = -1$. 4. The midline (center) is at $y = 0$, so the amplitude is the distance from $0$ to $1$ or $0$ to $-1$. 5. Therefore, the amplitude is: $$\text{amplitude} = |1 - 0| = 1$$ 6. The amplitude of the sinusoidal function is 1.