Question 4(ii)The following table gives the duration of movies in minutes.Duration (in minutes)No. of movies100-1105110-12010120-13017130-1408140-1506150-1604Using step–deviation method, find the mean duration of the movies.

Question

Accepted Answer

In the given table i is the class interval which is equal to 10.

Class	Class mark (x)	d = (x - A)	u = d/i	Frequency (f)	fu
100-110	105	-30	-3	5	-15
110-120	115	-20	-2	10	-20
120-130	125	-10	-1	17	-17
130-140	A = 135	0	0	8	0
140-150	145	10	1	6	6
150-160	155	20	2	4	8
Total				Σf = 50	Σfu = -38

Mean = A + $\dfrac{Σfu}{Σf} \times i = 135 + \dfrac{-38}{50} \times 10$

= $135 + \dfrac{-380}{50}$

= 135 - 7.6

= 127.4

Hence, mean = 127.4

Solved 2024 Question Paper ICSE Class 10 Mathematics — Question 2

Question 4(ii)