Question

The following table shows the income of farmers in a grape season. Find the mean of their income.

Income (Thousand Rupees)	20 - 30	30 - 40	40 - 50	50 - 60	60 - 70	70 - 80
Farmers	10	11	15	16	18	14

Answer 1

Class (Income in thousand rupees)	Class Mark xi	Frequency (Number of farmers) fi	Class mark × Frequency xifi
20 - 30	25	10	250
30 - 40	35	11	385
40 - 50	45	15	675
50 - 60	55	16	880
60 - 70	65	18	1170
70 - 80	75	14	1050
		$\sum _{}{f}_i=84$	$\sum _{}{x}_i{f}_i=4410$

Mean = $\frac{\sum _{}{x}_i{f}_i}{\sum _{}{f}_i}$
​$$\begin{gathered} =\frac{4410}{84} \\ =52.5\mathrm{thousand}\mathrm{rupees} \\ =52500 \end{gathered}$$
Hence, the mean of the income is Rs 52500.