Find the mean of the following frequency distribution,

The following frequency distribution is given

We have to find the mean of the above frequency distribution using step deviation method.

By using step deviation method, we have 

From the above distribution, we have

$h=10$

$a=25$

$\sum f_{i}=50$

$\sum f_{i} u_{i}=0$

We know the mean of a given distribution is given by

$\operatorname{Mean}(\bar{x})=a+\frac{\sum f_{t} u_{i}}{\sum f_{i}} \times h$

$=25+\frac{0}{50} \times 10$

$=25$

Hence the mean of the given distribution is 25.