Look at the cumulative frequency distribution table given below:
Monthly income | Number of families |
More than Rs. 10000 | 100 |
More than Rs. 14000 | 85 |
More than Rs. 18000 | 69 |
More than Rs.20000 | 50 |
More than Rs. 25000 | 37 |
More than Rs. 30000 | 15 |
Number of families having income range 20000 to 25000 is
MONTHLY INCOME | NUMBER OF FAMILIES | FREQUENCY (fi) |
10000 - 14000 | 100 | 100 - 85 = 15 |
14000 - 18000 | 85 | 85 - 69 = 16 |
18000 - 20000 | 69 | 69 - 50 = 19 |
20000 - 25000 | 50 | 50 - 37 = 13 |
25000 - 30000 | 37 | 37 - 15 = 22 |
30000 and above | 15 | 15 |
From the above table, number of families having income range 20000 - 25000 is 13. (Observe the frequency values corresponding to the monthly income)