Question

The following table shows the number of students and the time they utilized daily for their studies. Find the mean time spent by students for their studies by direct method.

Time (hrs.)	0-2	2-4	4-6	6-8	8-10
No. of students	7	18	12	10	3

Answer 1

Class (Time in hours)	Class Mark xi	Frequency (Number of students) fi	Class mark × Frequency xifi
0-2	1	7	7
2-4	3	18	54
4-6	5	12	60
6-8	7	10	70
8-10	9	3	27
		∑fi = 50	∑xifi = 218

Mean = `(sum x_i f_i)/(sum f_i)`

= `218/50`

= `109/25`

= 4.36 hours

Hence, the mean time spent by students on their studies is 4.36 hours.