Imagine you are sipping tea or coffee while discussing various issues with a broad and diverse network of students, colleagues, and friends brought together by the common bond of physics, graduate school, and the physics GRE.
These are the definitions of phase and group velocity respectively. So given different expressions , we can come up with examples of where one exceeds the other.
(c is constant)
It's helpful to know the graphical interpretations of these if you're studying for the GRE, so I'd recommend looking at the graphs of these functions and understanding when either is larger, smaller, or the same.