Find the Variance of the data: 6, 8, 10, 12, 14, 16, 18,20, 22,24
 

Let 14 be assumed mean. The number of observations is n=10.
 

$\text{ Therefore, Mean }\overline{x}=\text{ assumed mean }+\frac{\sum _{i=1}^n d_i}{n}\times h$

$=14+\frac{5}{10}\times 2=15$

$\text{ and Variance }\left({\sigma }^2\right)=\frac{1}{n}\times {\left(x_i-\overline{x}\right)}^2=\frac{1}{10}\times 330=33$