Question

Using the following frequency distribution of marks of students of a school, find range and relative range of the marks:

Marks	20 - 30	30 - 40	40 - 50	50 - 60	60 - 70	70 - 80
No. of students	8	20	25	60	45	10

Answer 1

Here, x_H = Upper limit of the last class 70 – 80 = 80 marks

x_L = Lower limit of the initial class 20 – 30 = 20 marks

Range of marks of students :

R = x_H – x_L

= 80 – 20 = 60 marks

Relative range of marks:

Relative range = \(\frac{R}{x_H+x_L}\)

= \(\frac{60}{80+20}\)

= \(\frac{60}{100}\)

= 0.60