Q14 of 37 Page 14

Compute the mean of the following data: [CBSE 2013]

Class

1 - 3

3 - 5

5 - 7

7 - 9

Frequency

12

22

27

19

For equal class intervals, we will solve by finding mid points of these classes using direct method.

We have got

Σf_i = 20 & Σf_ix_i = 426

∵ mean is given by

⇒

Thus, mean is 5.325

Compute the mean of the following data, using direct method: [CBSE 2005]

Class	0 - 100	100 - 200	200 - 300	300 - 400	400 - 500
Frequency	6	9	15	12	8

If the mean of the following frequency distribution is 54, find the value of p. [CBSE 2006]

Class	0 - 20	20 - 40	40 - 60	60 - 80	80 - 100
Frequency	7	p	10	9	13

If the mean of the following frequency distribution is 24, find the value of p. [CBSE 2013]

Class	0 - 10	10 - 20	20 - 30	30 - 40	40 - 50
Frequency	3	4	p	3	2

Find the mean of the following data, using step - deviation method: [CBSE 2013]

Class	5 - 15	15 - 25	25 - 35	35 - 45	45 - 55	55 - 65	65 - 75
Frequency	6	10	16	15	24	8	7