While calculating mean of a grouped frequency distribution, step deviation method was used ((x- a)/h= u ). It was found that x̄=64, h =5 and a =62.5.…

While calculating mean of a grouped frequency distribution, step deviation method was used $\displaystyle \left(\frac{x-\mathrm{a}}{\mathrm{h}}=\mathrm{u}\right)$. It was found that $\displaystyle \bar{x}=64, \mathrm{~h}=5$ and $\displaystyle \mathrm{a}=62.5$. The value of $\displaystyle \overline{\mathrm{u}}$ is