Class interval: 0-10 10-12 20-30 30-40 40-50 Frequency: 9 12 15 10 14

Class interval:

0-10

10-12

20-30

30-40

40-50

Frequency:

9

12

15

10

14

Let the assumed mean (A) = 25

Class interval	Mid value (x_i)	d_i = x_i - 25	u_i =	Frequency (f_i)	f_iu_i
0 – 10	5	-20	-2	9	-18
10 – 20	15	-10	-1	12	-12
20 – 30	25	0	0	15	0
30 – 40	35	10	1	10	10
40 – 50	45	20	2	14	28
				N = 60	∑f_iu_i = 8

We have, A = 25

h = 10

Mean = A + h *

= 25 + 10 *

= 25 +

= 25 + = 26.333

9