Question
A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent.
|
Number of days |
0-6 |
6-10 |
10-14 |
14-20 |
20-28 |
28-38 |
38-40 |
|
Number of students |
11 |
10 |
7 |
4 |
4 |
3 |
1 |
Solution
|
Number of days |
Number of students (fi) |
Class mark (xi) |
fixi |
|
0-6 |
11 |
3 |
33 |
|
6-10 |
10 |
8 |
80 |
|
10-14 |
7 |
12 |
84 |
|
14-20 |
4 |
17 |
68 |
|
20-28 |
4 |
24 |
96 |
|
28-38 |
3 |
33 |
99 |
|
38-40 |
1 |
39 |
39 |
|
Total |
Σfi = 40 |
Σfixi = 499 |
Here, we have
Now,
Hence, the mean number of days a student was absent is 12.48.
