Question

Distinguish between inclusive method and exclusive method.

Answer 1

Hint: First we will understand the terms ‘inclusive class intervals’ and ‘exclusive class intervals’ used in a frequency distribution table. Further we will consider an example of data assumed by us and we will draw the frequency distribution table of each type to make the concepts clear.

Complete step by step solution:
Here we have been asked to plot some differences between inclusive method and exclusive method. Let us understand these two terms (used in statistics) using an example.
(1) Inclusive method: - It is a method of classification of given data in such a manner that the upper limit of the previous class intervals does not repeat in the lower limit of the next class interval. In this classification we include both the values of upper and lower limit in the distribution table. For example: - 0 – 10, 11 – 20, 21 – 30, and so on.
(2) Exclusive method: - It is a method of classification of given data in such a manner that the upper limit of the previous class intervals gets repeated in the lower limit of the next class interval. In this classification we include only the value lower limit and do not include the value of upper limit in the distribution table. For example: - 0 – 10, 10 – 20, 20 – 30, and so on.
Now, let us take an example where we will draw the frequency distribution table of each kind using some assumed data by us. Assume that the marks (out of 40) obtained by 15 students of a class is given as: - 5, 10, 21, 29, 9, 8, 20, 16, 18, 25, 30, 25, 35, 37, 40 and we have to draw the frequency distribution table.
(i) Considering the Inclusive method of distribution we can draw the table as shown below: -

Marks	No. of students (frequency)
0 – 10	4
11 – 20	3
21 – 30	5
31 – 40	3

(ii) Considering the Exclusive method of distribution we can draw the table as shown below: -

Marks	No. of students (frequency)
0 – 10	3
10 – 20	3
20 – 30	5
30 – 40	3
40 – 50	1

Note: Note that we have considered the upper limit and lower limit both in inclusive methods of writing the frequency table while we have considered only the lower limit of a particular class while the upper limit is neglected. Do not think that if we will find the mean, median and mode using the two different methods then it will give different results. They will be equal for both the frequency tables.