$x_i$

mean, $\overline{x}$

$x_i-\overline{x}$

${\left(x_i-\overline{x}\right)}^2$

10

13.75

−3.75

14.0625

18

4.25

18.0625

27

13.25

175.5625

0

−13.75

189.0625