Let ${x_1},{x_2}, \ldots .,{x_{10}}$ be ten observations such that $\sum\limits_{i = 1}^{10} {\left( {{x_i} - 2} \right)} = 30,\sum\limits_{i = 1}^{10} {{{\left( {{x_i} - \beta } \right)}^2}} = 98,\beta > 2$, and their variance is $\frac{4}{5}$. If $\mu $ and ${\sigma ^2}$ are respectively the mean and the variance of $2\left( {{x_1} - 1} \right) + 4\beta $, $2\left( {{x_2} - 1} \right) + 4\beta , \ldots .,2\left( {{x_{10}} - 1} \right) + 4\beta $, then $\frac{{\beta \mu }}{{{\sigma ^2}}}$ is equal to :