Question

Marks of students of class VIII-B are distributed in the grouped frequency distribution table given below.

Class intervals (Marks)	Number of Students
0-30	25
30-40	35
40-60	27
60-100	13

What is the length of the bar in the histogram for the 4th class interval ?

• A. 13
• B. 26
• C. 3.25
• D. 100

Answer 1

The correct option is C 3.25

Class length is varying in given distribution, in such cases, frequency per unit class has to be calculated and histogram has to be constructed with respective heights. For our convenience, the least class length is taken as unit class length.

$\text{Modified length}=\frac{\text{Frequency of class}}{\text{Length of that class}}\times \text{Least Class length}$

We are given,
Length of 4th Class = 100-60 = 40
Frequency = 13
Least class length = 40-30 = 10
Modified length = $\frac{13}{40}\times 10$ = 3.25