Question

The table below shows the daily expenditure on food of 25 households in a locality.

Daily expenditure (in Rs)	100 − 150	150 − 200	200 − 250	250 − 300	300 − 350
Number of households	4	5	12	2	2

Find the mean daily expenditure on food by a suitable method.

Answer 1

To find the class mark (x_i) for each interval, the following relation is used.

Class size = 50

Taking 225 as assumed mean (a), d_i, u_i, f_iu_i are calculated as follows.

Daily expenditure (in Rs)	fi	xi	di = xi − 225		fiui
100 − 150	4	125	− 100	− 2	− 8
150 − 200	5	175	− 50	− 1	− 5
200 − 250	12	225	0	0	0
250 − 300	2	275	50	1	2
300 − 350	2	325	100	2	4
Total	25				− 7

From the table, we obtain

Therefore, mean daily expenditure on food is Rs 211.