If X∼Binomial(n,p)X \sim \text{Binomial}(n, p)X∼Binomial(n,p), what is the coefficient of variation σμ\frac{\sigma}{\mu}μσ?
\sqrt{\frac{1-p}{np}}
\frac{np}{1-p}
\sqrt{np(1-p)}
\frac{1-p}{p}