Question

The following table gives the literacy rate (in percentage) of 35 cities. Find the mean literacy rate.

Answer 1

To find the class mark $\left(x_i\right)$ for each interval, using the following relation:
$\left(x_i\right)=\frac{Upperclasslimit+Lowerclasslimit}{2}$
Class size $\left(h\right)$ for this data $=10$
Taking 70 as assumed mean $\left(a\right)$, calculating $d_i,u_i,f_i{u}_i$:
From the table:
$\sum f_i=35$
$\sum f_i{u}_i=-2$
Mean, $\overline{x}=a+\left(\frac{\sum f_i{u}_i}{\sum f_i}\right)\times h$
$=70+\left(\frac{-2}{35}\right)\times 10$
$=70-\frac{20}{35}$
$=70-\frac{4}{7}$
$=70-0.57$
$=69.43$
Therefore, mean literacy rate is $69.43$%