Question

The following table gives, the literacy rate (in percentage) in 40 cities. Find the mean literacy rate, choosing a suitable method. $\begin{array}{cccccc}\text{Literacy rate(\%)}& 45-55& 55-65& 65-75& 75-85& 85-95\\ \text{Number of cities}& 4& 11& 12& 9& 4\end{array}$

Answer 1

Using Direct method, the given data is shown as follows:

Literacy rate (%)	Number of cities (fi)	Class mark (xi)	(fixi)
45 - 55	4	50	200
55 - 65	11	60	660
65 - 75	12	70	840
75 - 85	9	80	720
85 - 95	4	90	360
Total	∑fi=40		∑(fi×xi)=2780

The mean of given data is given by

$\overline{x}$ = ∑(fi×xi)/∑fi

= 2780/40

= 69.5

Thus, the mean literacy rate is 69.5%.