3. The following data gives the distribution of total monthly household expenditure of 200 families of a village. Find the modal monthly expenditure of the families. Also, find the mean monthly expenditure :
The class having maximum frequency is the modal class.
The maximum frequency is 40 and hence the modal class = 1500-2000
Lower limit (l) of modal class = 1500, class size (h) = 500
Frequency ( ) of the modal class = 40 frequency ( ) of class preceding the modal class = 24, frequency ( ) of class succeeding the modal class = 33.
Thus, Mode of the data is Rs. 1847.82
Now,
Let the assumed mean be a = 2750 and h = 500
Expenditure |
Number of families |
Class mark
|
|||
1000-1500 | 24 | 1250 | -1500 | -3 | -72 |
1500-2000 | 40 | 1750 | -1000 | -2 | -80 |
2000-2500 | 33 | 2250 | -500 | -1 | -33 |
2500-3000 | 28 | 2750 | 0 | 0 | 0 |
3000-3500 | 30 | 3250 | 500 | 1 | 30 |
3500-4000 | 22 | 3750 | 1000 | 2 | 44 |
4000-4500 | 16 | 4250 | 1500 | 3 | 48 |
4500-5000 | 7 | 4750 | 2000 | 4 | 28 |
=200 |
= -35 |
Mean,
Thus, Mean monthly expenditure is Rs. 2662.50