Question

Solve any two of the following. 

Find the mean of the data given in the following table. 

Class	0-20	20-40	40-60	60-80	80-100
Frequency	6	4	5	7	3

Answer 1

Class	Class Mark` (x_1)`	Frequency  `f_1`	`x_1f_1`
0-20	10	6	60
20-40	30	4	120
40-60	50	5	250
60-80	70	7	490
80-100	90	3	270
		25	1190

Mean=`(∑x_1f_1)/(∑f_1)` 

=`1190/25` 

=`47.6`