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Home » 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.
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.
CBSE | Class 10 | Exercise 1 | Maths | Measures of Central Tendency | ML Aggarwal
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.
No. of days 0-6 6-10 10-14 14-20 20-28 28-38 38-40
No. of students 11 10 7 4 4 3 1

Solution:

Class mark, xi = (upper class limit + lower class limit)/2

No. of days Frequency 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 Ʃfi = 40 Ʃfixi = 499

Mean = Ʃfixi/ Ʃfi

= 499/40

=12.475

Hence the mean number of days a student was absent is 12.475.

i

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