Question

The following table gives the literacy rate (in percentage) in 40 cities. Find the mean literacy rate, choosing a suitable method.

Literacy rate (%)	45 – 55	55 – 65	65 – 75	75 – 85	85 – 95
Number of cities	4	11	12	9	4

Answer 1

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

Literacy rate (%)	Number of cities `(f_i)`	Class mark `(x_i)`	`(f_i x_i)`
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	`Ʃ f_i` = 40		`Ʃ f_i x_i` = 2780

The mean of the data is given by,

`barx = (Ʃf_i x_i)/(Ʃf_i)`

     =`2780/40`

     = 69.5

Thus, the mean literacy rate is 69.5%.