Let x₁, x₂,......x₁₀ be ten observations such that $\sum _{\mathrm{i}=1}^{10} \left({\mathrm{x}}_{\mathrm{i}}-2\right)=30,\sum _{\mathrm{i}=1}^{10} {\left({\mathrm{x}}_{\mathrm{i}}-\mathrm{\beta }\right)}^2=98,\mathrm{\beta }>2$ and their variance is 4/5. If $\mathrm{\mu }$ and $\mathrm{\sigma }$² are respectively the mean and the variance of 2(x₁–1) + 4$\mathrm{\beta }$, 2(x²–1) + 4$\mathrm{\beta }$, ....., 2(x10–1)+ 4$\mathrm{\beta }$, then $\frac{\mathrm{\beta \mu }}{{\mathrm{\sigma }}^2}$ is equal to :