Organisation of Data — Economics STD 11 Commerce — Question

Following steps are followed to convert an exclusive series into an inclusive series.

1. Find the difference between upper limit of preceding class and lower limit of succeeding class.
2. Divide this difference by 2.
3. Add this number in upper limit of all classes and deduct this number from lower limit of all classes.

For example, if classes are 0 - 9,10 - 19, 20 29 and so on. Then the difference between upper limit and lower limit of two succeeding classes is one. When we divide it by 2, we get 0.5. Therefore on deducting this number from upper limit and adding this number in lower limit, we can get new class intervals as- (-) 0.5 -9.5, 9.5 - 19.5, 19.5 and so on.