Class interval: 0-8 8-16 16-24 24-32 32-40 Frequency: 5 6 4 3 2

Class interval:

0-8

8-16

16-24

24-32

32-40

Frequency:

5

6

4

3

2

Let the assumed (A) = 20

Class interval	Mid value (x_i)	d_i = x_i - 20	Frequency (f_i)	u_i =	f₁u₁
0 – 8	4	-16	5	-2	-10
8 -16	12	-8	6	-1	-6
16-24	20	0	4	0	0
24-32	28	8	3	1	3
32-40	36	16	2	2	4
			N = 20		∑f_iu_i = - 9

We have, A = 20

h = 8

Mean = A + h *

= 20 + 8 *

= 20 - = 20 – 3.6

= 16.4

11