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 |
The above given data can be represented in the form of table as below:
Class Interval | fi | xi | fixi |
0-6 | 11 | 3 | 33 |
6-14 | 10 | 8 | 80 |
14-20 | 7 | 12 | 84 |
20-28 | 4 | 17 | 68 |
28-38 | 4 | 24 | 96 |
38-40 | 3 | 33 | 99 |
1 | 39 | 39 | |
∑fi = 40 | ∑fixi = 499 |
Mean can be calculated as follows:
= 12.4 (approx.)
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