If n =10, = 12 and = 1530 find coefficient of variation
∑ x n = x ¯ {\displaystyle {\frac {\sum _{}^{}x}{n}}={\bar {x}}} <bar> ∑ f x n = x ¯ {\displaystyle {\frac {\sum _{}^{}fx}{n}}={\bar {x}}}