Let the six numbers a_1, a_2, a_3, a_4, a_5, a_6, be in A.P. and a_1+a_3=10. If the mean of these six numbers is 19/2 and their variance is σ^2, then…

Let the six numbers $\displaystyle a_1, a_2, a_3, a_4, a_5, a_6$, be in A.P. and $\displaystyle a_1+a_3=10$. If the mean of these six numbers is $\displaystyle \frac{19}{2}$ and their variance is $\displaystyle \sigma^2$, then $\displaystyle 8 \sigma^2$ is equal to :