Answer
The amplitude is $\frac{1}{2}$, the period is $\pi$, the vertical translation is $1$ unit down as $c$ is less than zero and the phase shift is $\frac{3\pi}{2}$ units to the right since $d$ is more than zero.
Work Step by Step
We first write the equation in the form $y=c+a \cos[b(x-d)]$. Therefore, $y=-1+\frac{1}{2}\cos(2x-3\pi)$ becomes $y=-1+\frac{1}{2}\cos[2(x-\frac{3\pi}{2})]$
Comparing the two equations, $a=\frac{1}{2},b=2,c=-1$ and $d=\frac{3\pi}{2}$.
The amplitude is $|a|=|\frac{1}{2}|=\frac{1}{2}.$
The period is $\frac{2\pi}{b}=\frac{2\pi}{2}=\pi$.
The vertical translation is $c=-1$.
The phase shift is $|d|=|\frac{3\pi}{2}|=\frac{3\pi}{2}$
Therefore, the amplitude is $\frac{1}{2}$, the period is $\pi$, the vertical translation is $1$ unit down as $c$ is less than zero and the phase shift is $\frac{3\pi}{2}$ units to the right since $d$ is more than zero.