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

Time	Class mark (xi)	No. of students (fi)	xi × fi
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
Total		`bb(sumf_i=50)`	`bb(sumx_ixxf_i=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.