Given a dataset $X$ with $n$ observations, the relationship between the population variance $\sigma^2$ and the raw moments $\mu'_k = E[X^k]$ is given by $\sigma^2 = \mu'_2 - (\mu'_1)^2$. If a dataset has $\mu'_1 = 5$ and $\mu'_2 = 30$, what is the coefficient of variation (CV)?