For a statistical data ${{\rm{x}}_1},{{\rm{x}}_2}, \ldots ,{{\rm{x}}_{10}}$ of 10 values, a student obtained the mean as 5.5 and $\sum\limits_{i = 1}^{10} {x_i^2} = 371$. He later found that he had noted two values in the data incorrectly as 4 and 5, instead of the correct values 6 and 8, respectively. The variance of the corrected data is